DMAKE - Version 4.4
IndexNAME
dmake - maintain program groups, or interdependent filesSYNOPSIS
dmake [-P#] [-{f|C|K} file] [-{w|W} target ...] [macro[[!][*][+][:]]=value ...] [-ABcdeEghiknpqrsStTuVxX] [-v[cdfimrtw]] [-m[trae]] [target ...]DESCRIPTION
dmake is a re-implementation of the UNIX Make utility with significant enhancements. dmake executes commands found in an external file called a makefile to update one or more target names. Each target may depend on zero or more prerequisite targets. If any of the target's prerequisites is newer than the target or if the target itself does not exist, then dmake will attempt to make the target.
If no -f command line option is present then dmake searches for an existing makefile from the list of prerequisites specified for the special target .MAKEFILES (see the STARTUP section for more details). If "-" is the name of the file specified to the -f flag then dmake uses standard input as the source of the makefile text.
Any macro definitions (arguments with embedded "=" signs) that appear on the command line are processed first and supercede definitions for macros of the same name found within the makefile. In general it is impossible for definitions found inside the makefile to redefine a macro defined on the command line, see the MACROS section for exceptions.
If no target names are specified on the command line, then dmake uses the first non-special target found in the makefile as the default target. See the SPECIAL TARGETS section for the list of special targets and their function. Makefiles written for most previous versions of Make will be handled correctly by dmake. Known differences between dmake and other versions of make are discussed in the COMPATIBILITY section found at the end of this document. dmake returns 0 if no errors were detected and a non-zero result if an error occurred.
OPTIONS
- -A
- Enable AUGMAKE special inference rule transformations (see the "PERCENT(%) RULES" section), these are set to off by default.
- -B
- Enable the use of spaces instead of <tabs> to begin recipe lines. This flag equivalent to the .NOTABS special macro and is further described below.
- -c
- Use non-standard comment stripping. If you specify -c then dmake will treat any # character as a start of comment character wherever it may appear unless it is escaped by a \.
- -C [+]file
- This option writes to file a copy of standard output and standard error from any child processes and from the dmake process itself. If you specify a + prior to the file name then the text is appended to the previous contents of file. This option is active in the MSDOS implementation only and is ignored by non-MSDOS versions of dmake.
- -d
- Disable the use of the directory cache. Normally dmake caches directories as it checks file timestamps. Giving this flag is equivalent to the .DIRCACHE attribute or macro being set to no.
- -E
- Read the environment and define all strings of the form 'ENV-VAR=evalue' defined within as macros whose name is ENV-VAR, and whose value is 'evalue'. The environment is processed prior to processing the user specified makefile thereby allowing definitions in the makefile to override definitions in the environment.
- -e
- Same as -E, except that the environment is processed after the user specified makefile has been processed (thus definitions in the environment override definitions in the makefile). The -e and -E options are mutually exclusive. If both are given the latter takes effect.
- -f file
- Use file as the source for the makefile text. Only one -f option is allowed.
- -g
- Globally disable group recipe parsing, equivalent to the .IGNOREGROUP attribute or macro being set to yes at the start of the makefile.
- -h
- Print the command summary for dmake.
- -i
- Tells dmake to ignore errors, and continue making other targets. This is equivalent to the .IGNORE attribute or macro.
- -K file
- Turns on .KEEP_STATE state tracking and tells dmake to use file as the state file.
- -k
- Causes dmake to ignore errors caused by command execution and to make all targets not depending on targets that could not be made. Ordinarily dmake stops after a command returns a non-zero status, specifying -k causes dmake to ignore the error and continue to make as much as possible.
- -m[trae]
- Measure timing information. Print the time when targets and/or recipes are started and finished to stdout. The following format is used:
- {s|e} {target|recipe} time maketarget
-
s or e stands for started or ended, target or
recipe denotes if this line refers to the whole target or a
recipe. time is displayed in Unix time format, i.e. the number
of seconds since an epoch. (Since 1970-01-01T00:00:00Z). maketarget
obviously represents the target the timing information is given for.
The optional flags [trae] can be used to change the information that
is displayed. If no optional flags are given only the t flag
is assumed to be selected, ie. -mt. The optional flags stand for:
-
- t
- Display the start and end time of each target.
- r
- Display the start and end time of each recipe.
- a
- Display the target as an absolute path, i.e. prepend the current working directory.
- e
- Also display the start and end time of the $(shell command) function (aka. shell escape) macros.
-
- -n
- Causes dmake to print out what it would have executed, but does not actually execute the commands. A special check is made for the string "$(MAKE)" inside a recipe line, if it is found, the line is expanded and invoked, thereby enabling recursive makes to give a full description of all that they will do. This check is disabled inside group recipes.
- -p
- Print out a version of the digested makefile in human readable form. (useful for debugging, but cannot be re-read by dmake)
- -P#
- On systems that support multi-processing cause dmake to use # concurrent child processes to make targets. See the "MULTI PROCESSING" section for more information.
- -q
- Check and see if the target is up to date. Exits with code 0 if up to date, 1 otherwise.
- -r
- Tells dmake not to read the initial startup makefile, see STARTUP section for more details.
- -s
- Tells dmake to do all its work silently and not echo the commands it is executing to stdout (also suppresses warnings). This is equivalent to the .SILENT attribute or macro.
- -S
- Force sequential execution of recipes on architectures which support concurrent makes. For backward compatibility with old makefiles that have nasty side-effect prerequisite dependencies.
- -t
- Causes dmake to touch the targets and bring them up to date without executing any commands. Note that targets will not be created if they do not already exist.
- -T
- Tells dmake to not perform transitive closure on the inference graph.
- -u
- Force an unconditional update. (ie. do everything that would be done if everything that a target depended on was out of date)
- -v[cdfimrtw]
-
Verbose flag, when making targets print to stdout what we are going to make
and what we think its time stamp is. The optional flags [cdfimrtw] can be
used to restrict the information that is displayed. In the absence of any
optional flags all are assumed to be given (ie. -v is equivalent to
-vcdfimrtw). The meanings of the optional flags are:
-
- c
- Notify of directory cache operations only.
- d
- Notify of change directory operations only.
- f
- Notify of file I/O operations only.
- i
- Notify of inference algorithm operation only.
- m
- Notify of target update operations only.
- r
- Force output of recipe lines and warnings. This switch is usefull when debugging makefiles that disable the output using the @ sign for recipe lines or the .SILENT target/attribute. It also overrides the -s flag.
- t
- Keep any temporary files created; normally they are automatically deleted.
- w
- Notify of non-essential warnings (these are historical).
-
- -V
- Print the version of dmake, and values of builtin macros.
- -W target
- Run dmake pretending that target is out of date.
- -w target
- What if? Show what would be made if target were out of date.
- -x
- Upon processing the user makefile export all non-internally defined macros to the user's environment. This option together with the -e option allows SYSV AUGMAKE recursive makes to function as expected.
- -X
- Inhibit the execution of #! lines found at the beginning of a makefile. The use of this flag prevents non-termination of recursive make invocations.
INDEX
Here is a list of the sections that follow and a short description of each. Perhaps you won't have to read the entire man page to find what you need.- STARTUP
- Describes dmake initialization.
- SYNTAX
- Describes the syntax of makefile expressions.
- ATTRIBUTES
- Describes the notion of attributes and how they are used when making targets.
- MACROS
- Defining and expanding macros.
- RULES AND TARGETS
- How to define targets and their prerequisites.
- RECIPES
- How to tell dmake how to make a target.
- TEXT DIVERSIONS
- How to use text diversions in recipes and macro expansions.
- SPECIAL TARGETS
- Some targets are special.
- SPECIAL MACROS
- Macros used by dmake to alter the processing of the makefile, and those defined by dmake for the user.
- CONTROL MACROS
- Itemized list of special control macros.
- RUNTIME MACROS
- Discussion of special run-time macros such as $@ and $<.
- FUNCTION MACROS
- GNU style function macros, only $(mktmp ...) for now.
- CONDITIONAL MACROS
- Target specific conditional macros.
- DYNAMIC PREREQUISITES
- Processing of prerequisites which contain macro expansions in their name.
- BINDING TARGETS
- The rules that dmake uses to bind a target to an existing file in the file system.
- PERCENT(%) RULES
- Specification of recipes to be used by the inference algorithm.
- MAKING INFERENCES
- The rules that dmake uses when inferring how to make a target which has no explicit recipe. This and the previous section are really a single section in the text.
- MAKING TARGETS
- How dmake makes targets other than libraries.
- MAKING LIBRARIES
- How dmake makes libraries.
- KEEP STATE
- A discussion of how .KEEP_STATE works.
- MULTI PROCESSING
- Discussion of dmake's parallel make facilities for architectures that support them.
- CONDITIONALS
- Conditional expressions which control the processing of the makefile.
- EXAMPLES
- Some hopefully useful examples.
- COMPATIBILITY
- How dmake compares with previous versions of make.
- LIMITS
- Limitations of dmake.
- PORTABILITY
- Comments on writing portable makefiles.
- FILES
- Files used by dmake.
- SEE ALSO
- Other related programs, and man pages.
- AUTHOR
- The guy responsible for this thing.
- BUGS
- Hope not.
STARTUP
When dmake begins execution it first processes the command line and then processes an initial startup-makefile. This is followed by an attempt to locate and process a user supplied makefile. The startup file defines the default values of all required control macros and the set of default rules for making targets and inferences. When searching for the startup makefile, dmake searches the following locations, in the order specified, until a startup file is located:
-
- 1.
- The location given as the value of the macro MAKESTARTUP defined on the command line.
- 2.
- The location given as the value of the environment variable MAKESTARTUP defined in the current environment.
- 3.
-
The location given as the value of the macro
MAKESTARTUP defined internally within dmake. In this version, the
internal definition of MAKESTARTUP is "$(DMAKEROOT)/startup.mk", so you
can set the environment variable DMAKEROOT to the location of your startup
directory.
If DMAKEROOT is not changed, for native Windows dmake versions its value defaults to "$(ABSMAKECMD:d)startup" (see definition of ABSMAKECMD for details). For unix like versions build with the autotools build system it defaults to the value of "${prefix}/share/startup" at build time. The actual value, usually something like /usr/local/share/startup can be checked with the -V command line switch.
The above search is disabled by specifying the -r option on the command line. An error is issued if a startup makefile cannot be found and the -r option was not specified. A user may substitute a custom startup file by defining the MAKESTARTUP environment variable or by redefining the MAKESTARTUP macro on the command line. To determine where dmake looks for the default startup file, check your environment or issue the command "dmake -V".
A similar search is performed to locate a default user makefile when no -f command line option is specified. By default, the prerequisite list of the special target .MAKEFILES specifies the names of possible makefiles and the search order that dmake should use to determine if one exists. A typical definition for this target is:
-
.MAKEFILES : makefile.mk Makefile makefile
If the first line of the user makefile is of the form:
-
#!command command_args
dmake builds the internal dependency graph as it parses a user specified makefile. The graph is rooted at the special target .ROOT. .ROOT is the top level target that dmake builds when it starts to build targets. All user specified targets (those from the command line or taken as defaults from the makefile) are made prerequisites of the special target .TARGETS. dmake by default creates the relationship that .ROOT depends on .TARGETS and as a result everything is made. This approach allows the user to customize, within their makefile, the order and which, target, is built first. For example the default makefiles come with settings for .ROOT that specify:
- .ROOT .PHONY .NOSTATE .SEQUENTIAL : .INIT .TARGETS .DONE
with .INIT and .DONE defined as:
- .INIT .DONE .PHONY:;
which nicely emulates the behaviour of Sun's make extensions. The building of .ROOT's prerequisites is always forced to be sequential. However, this definition is trivially chaned by supplying the definition:
- .ROOT : .TARGETS
which skips the preamble and postamble phases of building .TARGETS.
SYNTAX
This section is a summary of the syntax of makefile statements. The description is given in a style similar to BNF, where { } enclose items that may appear zero or more times, and [ ] enclose items that are optional. Alternative productions for a left hand side are indicated by '->', and newlines are significant. All symbols in bold type are text or names representing text supplied by the user.
-
- Makefile
- -> { Statement }
- Statement
- -> Macro-Definition -> Conditional-Macro-Definition -> Conditional -> Rule-Definition -> Attribute-Definition
- Macro-Definition
- -> MACRO = LINE -> MACRO [!]*= LINE -> MACRO [!]:= LINE -> MACRO [!]*:= LINE -> MACRO [!]+= LINE -> MACRO [!]+:= LINE
- Conditional-Macro-Definition ->
- TARGET ?= Macro-Definition
- Conditional ->
- .IF expression Makefile [ .ELIF expression Makefile ] [ .ELSE Makefile ] .END
- expression
- -> LINE -> STRING == LINE -> STRING != LINE -> STRING <= LINE -> STRING >= LINE -> ( expression ) -> expression || expression -> expression && expression
- Rule-Definition ->
- target-definition [ recipe ]
- targets
- -> target { targets } -> "target" { targets }
- target
- -> special-target -> TARGET
- attrs
- -> attribute { attrs } -> "attribute" { attrs }
- op
- -> : { modifier }
- modifier
- -> : -> ^ -> ! -> - -> |
- recipe
- -> { TAB rcp-line }
-> [@][%][-] [
- ]
- rcp-line
- -> [@][%][-][+] LINE
- Attribute-Definition
- -> attrs : targets
- attribute
- -> .EPILOG -> .ERRREMOVE -> .EXECUTE -> .GROUP -> .IGNORE -> .IGNOREGROUP -> .LIBRARY -> .MKSARGS -> .NOINFER -> .NOSTATE -> .PHONY -> .PRECIOUS -> .PROLOG -> .SETDIR=path -> .SILENT -> .SEQUENTIAL -> .SWAP -> .USESHELL -> .SYMBOL -> .UPDATEALL
- special-target
- -> .ERROR -> .EXIT -> .EXPORT -> .GROUPEPILOG -> .GROUPPROLOG -> .IMPORT -> .INCLUDE -> .INCLUDEDIRS -> .MAKEFILES -> .REMOVE -> .SOURCE -> .SOURCE.suffix -> .suffix1.suffix2
Where, TAB represents a <tab> character, STRING represents an arbitrary sequence of characters, and LINE represents a possibly empty sequence of characters terminated by a non-escaped (not immediately preceded by a backslash '\') new-line character. MACRO, PREREQUISITE, and TARGET each represent a string of characters not including space or tab which respectively form the name of a macro, prerequisite or target. The name may itself be a macro expansion expression. A LINE can be continued over several physical lines by terminating it with a single backslash character. Comments are initiated by the pound # character and extend to the end of line. All comment text is discarded, a '#' may be placed into the makefile text by escaping it with '\' (ie. \# translates to # when it is parsed). An exception to this occurs when a # is seen inside a recipe line that begins with a <tab> or is inside a group recipe. If you specify the -c command line switch then this behavior is disabled and dmake will treat all # characters as start of comment indicators unless they are escaped by \. A set of continued lines may be commented out by placing a single # at the start of the first line. A continued line cannot span more than one makefile.
white space is defined to be any combination of <space>, <tab>, and the sequence \<nl> when \<nl> is used to terminate a LINE. When processing macro definition lines, any amount of white space is allowed on either side of the macro operator and white space is stripped from both before and after the macro value string. The sequence \<nl> is treated as white space during recipe expansion and is deleted from the final recipe string. You must escape the \<nl> with another \ in order to get a \ at the end of a recipe line. The \<nl> sequence is deleted from macro values when they are expanded.
When processing target definition lines, the recipe for a target must, in general, follow the first definition of the target (See the RULES AND TARGETS section for an exception), and the recipe may not span across multiple makefiles. Any targets and prerequisites found on a target definition line are taken to be white space separated tokens. The rule operator (op in SYNTAX section) is also considered to be a token but does not require white space to precede or follow it. Since the rule operator begins with a `:', traditional versions of make do not allow the `:' character to form a valid target name. dmake allows `:' to be present in target/prerequisite names as long as the entire target/prerequisite name is quoted. For example:
a:fred : test
would be parsed as TARGET = a, PREREQUISITES={fred, :, test}, which is not what was intended. To fix this you must write:
"a:fred" : test
Which will be parsed as expected. Quoted target and prerequisite specifications may also contain white space thereby allowing the use of complex function macro expressions.. See the EXAMPLES section for how to apply " quoting to a list of targets.
ATTRIBUTES
dmake defines several target attributes. Attributes may be assigned to a single target, a group of targets, or to all targets in the makefile. Attributes are used to modify dmake actions during target update. The recognized attributes are:
- .EPILOG
- Insert shell epilog code when executing a group recipe associated with any target having this attribute set.
- .ERRREMOVE
- Always remove any target having this attribute if an error is encountered while making them. Setting this attribute overrides the .PRECIOUS attribute.
- .EXECUTE
- If the -n flag was given then execute the recipe associated with any target having this attribute set.
- .FIRST
- Used in conjunction with .INCLUDE. Terminates the inclusion with the first successfully included prerequisite.
- .GROUP
- Force execution of a target's recipe as a group recipe.
- .IGNORE
- Ignore an error when trying to make any target with this attribute set.
- .IGNOREGROUP
- Disable the special meaning of '[' to initiate a group recipe.
- .LIBRARY
- Target is a library.
- .MKSARGS
- If running in an MSDOS environment then use MKS extended argument passing conventions to pass arguments to commands. Non-MSDOS environments ignore this attribute.
- .NOINFER
- Any target with this attribute set will not be subjected to transitive closure if it is inferred as a prerequisite of a target whose recipe and prerequisites are being inferred. (i.e. the inference algorithm will not use any prerequisite with this attribute set, as a target) If specified as '.NOINFER:' (ie. with no prerequisites or targets) then the effect is equivalent to specifying -T on the command line.
- .NOSTATE
- Any target with this attribute set will not have command line flag information stored in the state file if .KEEP_STATE has been enabled.
- .PHONY
- Any target with this attribute set will have its recipe executed each time the target is made even if a file matching the target name can be located. Any targets that have a .PHONY attributed target as a prerequisite will be made each time the .PHONY attributed prerequisite is made.
- .PRECIOUS
- Do not remove associated target under any circumstances. Set by default for any targets whose corresponding files exist in the file system prior to the execution of dmake.
- .PROLOG
- Insert shell prolog code when executing a group recipe associated with any target having this attribute set.
- .SEQUENTIAL
- Force a sequential make of the associated target's prerequisites.
- .SETDIR
- Change current working directory to specified directory when making the associated target. You must specify the directory at the time the attribute is specified. To do this simply give .SETDIR=path as the attribute. path is expanded and the result is used as the value of the directory to change to. If path contains $$@ then the name of the target to be built is used in computing the path to change directory to. If path is surrounded by single quotes then path is not expanded, and is used literally as the directory name. If the path contains any `:' characters then the entire attribute string must be quoted using ". If a target having this attribute set also has the .IGNORE attribute set then if the change to the specified directory fails it will be ignored, and no error message will be issued.
- .SILENT
- Do not echo the recipe lines when making any target with this attribute set, and do not issue any warnings.
- .SWAP
- Under MSDOS when making a target with this attribute set swap the dmake executable to disk prior to executing the recipe line. Also see the '%' recipe line flag defined in the RECIPES section.
- .SYMBOL
- Target is a library member and is an entry point into a module in the library. This attribute is used only when searching a library for a target. Targets of the form lib((entry)) have this attribute set automatically.
- .USESHELL
- Force each recipe line of a target to be executed using a shell. Specifying this attribute is equivalent to specifying the '+' character at the start of each line of a non-group recipe.
- .UPDATEALL
- Indicates that all the targets listed in this rule are updated by the execution of the accompanying recipe. A common example is the production of the y.tab.c and y.tab.h files by yacc when it is run on a grammar. Specifying .UPDATEALL in such a rule prevents the running of yacc twice, once for the y.tab.c file and once for the y.tab.h file. .UPDATEALL targets that are specified in a single rule are treated as a single target and all timestamps are updated whenever any target in the set is made. As a side-effect, dmake internally sorts such targets in ascending alphabetical order and the value of $@ is always the first target in the sorted set.
All attributes are user setable and except for .UPDATEALL and .MKSARGS may be used in one of two forms. The .MKSARGS attribute is restricted to use as a global attribute, and the use of the .UPDATEALL attribute is restricted to rules of the second form only.
ATTRIBUTE_LIST : targets
assigns the attributes specified by ATTRIBUTE_LIST to each target in targets or
targets ATTRIBUTE_LIST : ...
assigns the attributes specified by ATTRIBUTE_LIST to each target in targets. In the first form if targets is empty (ie. a NULL list), then the list of attributes will apply to all targets in the makefile (this is equivalent to the common Make construct of ".IGNORE :" but has been modified to the notion of an attribute instead of a special target). Not all of the attributes have global meaning. In particular, .LIBRARY, .NOSTATE, .PHONY, .SETDIR, .SYMBOL and .UPDATEALL have no assigned global meaning.
Any attribute may be used with any target, even with the special targets. Some combinations are useless (e.g. .INCLUDE .PRECIOUS: ... ), while others are useful (e.g. .INCLUDE .IGNORE : "file.mk" will not complain if file.mk cannot be found using the include file search rules, see the section on SPECIAL TARGETS for a description of .INCLUDE). If a specified attribute will not be used with the special target a warning is issued and the attribute is ignored.
MACROS
dmake supports six forms of macro assignment.
- MACRO = LINE
- This is the most common and familiar form of macro assignment. It assigns LINE literally as the value of MACRO. Future expansions of MACRO recursively expand its value.
- MACRO *= LINE
- This form behaves exactly as the simple '=' form with the exception that if MACRO already has a value then the assignment is not performed.
- MACRO := LINE
- This form differs from the simple '=' form in that it expands LINE prior to assigning it as the value of MACRO. Future expansions of MACRO do not recursively expand its value.
- MACRO *:= LINE
- This form behaves exactly as the ':=' form with the exception that if MACRO already has a value then the assignment and expansion are not performed.
- MACRO += LINE
- This form of macro assignment allows macro values to grow. It takes the literal value of LINE and appends it to the previous value of MACRO separating the two by a single space. Future expansions of MACRO recursively expand its value.
- MACRO +:= LINE
- This form is similar to the '+=' form except that the value of LINE is expanded prior to being added to the value of MACRO.
Macro expressions specified on the command line allow the macro value to be redefined within the makefile only if the macro is defined using the '+=' and '+:=' operators. Other operators will define a macro that cannot be further modified.
Each of the preceeding macro assignment operators may be prefixed by ! to indicate that the assignment should be forced and that no warnings should be issued. Thus, specifying ! has the effect of silently forcing the specified macro assignment.
When dmake defines a non-environment macro it strips leading and trailing white space from the macro value. Macros imported from the environment via either the .IMPORT special target (see the SPECIAL TARGETS section), or the -e, or -E flags are an exception to this rule. Their values are always taken literally and white space is never stripped. In addition, named macros defined using the .IMPORT special target do not have their values expanded when they are used within a makefile. In contrast, environment macros that are imported due to the specification of the -e or -E flags are subject to expansion when used.
To specify a macro expansion enclose the name in () or {} and precede it with a dollar sign $. Thus $(TEST) represents an expansion of the macro variable named TEST. If TEST is defined then $(TEST) is replaced by its expanded value. If TEST is not defined then $(TEST) expands to the NULL string (this is equivalent to defining a macro as 'TEST=' ). A short form may be used for single character named macros. In this case the parentheses are optional, and $(I) is equivalent to $I. Macro expansion is recursive, hence, if the value string contains an expression representing a macro expansion, the expansion is performed. Circular macro expansions are detected and cause an error to be issued.
When defining a macro the given macro name is first expanded before being used to define the macro. Thus it is possible to define macros whose names depend on values of other macros. For example, suppose CWD is defined as
CWD = $(PWD:b)
then the value of $(CWD) is the name of the current directory. This can be used to define macros specific to this directory, for example:
_$(CWD).prt = list of files to print...
The actual name of the defined macro is a function of the current directory. A construct such as this is useful when processing a hierarchy of directories using .SETDIR attributed targets and a collection of small distributed makefile stubs.
Macro variables may be defined within the makefile, on the command line, or imported from the environment.
dmake supports several non-standard macro expansions: The first is of the form:
-
- $(macro_name:modifier_list:modifier_list:...)
where modifier_list may be a combination of:
-
- b or B
- - file (not including suffix) portion of path names
- d or D
- - directory portion of all path names
- e or E
- - suffix portion of path names
- f or F
- - file (including suffix) portion of path names
- i or I
- - inferred names of targets
- l or L
- - macro value in lower case
- u or U
- - macro value in upper case
- 1
- - return the first white space separated token from value
-
- m or M
- - map escape codes found in macro to their ASCII value
- s or S
- - simple pattern substitution
- t or T
- - tokenization.
- ^
- - prepend a prefix to each token
- +
- - append a suffix to each token
- test = d1/d2/d3/a.out f.out d1/k.out
-
- $(test:d)
- -> d1/d2/d3/ d1/
- $(test:b)
- -> a f k
- $(test:f)
- -> a.out f.out k.out
- ${test:db}
- -> d1/d2/d3/a f d1/k
- ${test:s/out/in/:f}
- -> a.in f.in k.in
- $(test:f:t+)
- -> a.out+f.out+k.out
- $(test:e)
- -> .out .out .out
- $(test:u)
- -> D1/D2/D3/A.OUT F.OUT D1/K.OUT
- $(test:1)
- -> d1/d2/d3/a.out
If a token ends in a string composed from the value of the macro DIRBRKSTR (ie. ends in a directory separator string, e.g. '/' in UNIX) and you use the :d modifier then the expansion returns the directory name less the final directory separator string. Thus successive pairs of :d modifiers each remove a level of directory in the token string.
The map escape codes modifier changes the following escape codes \a => <bel>, \b => <backspace>, \f => <formfeed>, \n => <nl>, \r => <cr>, \t => <tab>, \v => <vertical tab>, \" => ", and \xxx => <xxx> where xxx is the octal representation of a character into the corresponding ASCII value.
The tokenization, prepend and append modifier may use the same escape codes that are supported by the map escape codes modifier in the string that is inserted, prepended or added by the respective macro modifier. These modifiers may quote this string to include otherwise problematic characters. E.g. spaces, colons and parentheses.
The tokenization modifier takes all white space separated tokens from the macro value and separates them by the separator string. Thus the expansion:
-
$(test:f:t"+\n")
- a.out+ f.out+ k.out
The prefix operator ^ takes all white space separated tokens from the macro value and prepends string to each.
-
$(test:f:^mydir/)
- mydir/a.out mydir/f.out mydir/k.out
The suffix operator + takes all white space separated tokens from the macro value and appends string to each.
-
$(test:b:+.c)
- a.c f.c k.c
The next non-standard form of macro expansion allows for recursive macros. It is possible to specify a $(macro_name) or ${macro_name} expansion where macro_name contains more $( ... ) or ${ ... } macro expansions itself.
For example $(CC$(_HOST)$(_COMPILER)) will first expand CC$(_HOST)$(_COMPILER) to get a result and use that result as the name of the macro to expand. This is useful for writing a makefile for more than one target environment. As an example consider the following hypothetical case. Suppose that _HOST and _COMPILER are imported from the environment and are set to represent the host machine type and the host compiler respectively.
-
CFLAGS_VAX_CC = -c -O # _HOST == "_VAX", _COMPILER == "_CC" CFLAGS_PC_MSC = -c -ML # _HOST == "_PC", _COMPILER == "_MSC" # redefine CFLAGS macro as: CFLAGS := $(CFLAGS$(_HOST)$(_COMPILER))
The final non-standard macro expansion is of the form:
-
string1{token_list}string2
where string1, string2 and token_list are expanded. After expansion, string1 is prepended to each token found in token_list and string2 is appended to each resulting token from the previous prepend. string1 and string2 are not delimited by white space whereas the tokens in token_list are. A null token in the token list is specified using "". Thus using another example we have:
-
- test/{f1 f2}.o
- --> test/f1.o test/f2.o
- test/ {f1 f2}.o
- --> test/ f1.o f2.o
- test/{f1 f2} .o
- --> test/f1 test/f2 .o
- test/{f1 }.o
- --> test/f1.o test/.o
- and
- test/{d1 d2}/{f1 f2}.o -->
- test/d1/f1.o test/d1/f2.o test/d2/f1.o test/d2/f2.o
-
{ echo hello;}
-
{echo hello;}
RULES AND TARGETS
A makefile contains a series of entries that specify dependencies. Such entries are called target/prerequisite or rule definitions. Each rule definition is optionally followed by a set of lines that provide a recipe for updating any targets defined by the rule. Whenever dmake attempts to bring a target up to date and an explicit recipe is provided with a rule defining the target, that recipe is used to update the target. A rule definition begins with a line having the following syntax:
-
<targets> [<attributes>] <ruleop> [<prerequisites>] [;<recipe>]
targets is a non-empty list of targets. If the target is a special target (see SPECIAL TARGETS section below) then it must appear alone on the rule line. For example:
- .IMPORT .ERROR : ...
is not allowed since both .IMPORT and .ERROR are special targets. Special targets are not used in the construction of the dependency graph and will not be made.
attributes is a possibly empty list of attributes. Any attribute defined in the ATTRIBUTES section above may be specified. All attributes will be applied to the list of named targets in the rule definition. No other targets will be affected.
- NOTE:
-
As stated earlier,
if both the target list and prerequisite list are empty but the attributes
list is not, then the specified attributes affect all targets in the makefile.
ruleop is a separator which is used to identify the targets from the prerequisites. Optionally it also provides a facility for modifying the way in which dmake handles the making of the associated targets. In its simplest form the operator is a single ':', and need not be separated by white space from its neighboring tokens. It may additionally be followed by any of the modifiers { !, ^, -, :, | }, where:
- !
- says execute the recipe for the associated targets once for each out of date prerequisite. Ordinarily the recipe is executed once for all out of date prerequisites at the same time.
- ^
- says to insert the specified prerequisites, if any, before any other prerequisites already associated with the specified targets. In general, it is not useful to specify ^ with an empty list of prerequisites.
- -
-
says to clear the previous list of prerequisites before adding
the new prerequisites. Thus,
.SUFFIXES :
.SUFFIXES : .a .bcan be replaced by
.SUFFIXES :- .a .b
however the old form still works as expected. NOTE: .SUFFIXES is ignored by dmake it is used here simply as an example.
- :
-
When the rule operator is not modified by a second ':'
only one set of rules may be specified for making a target.
Multiple definitions may be used to add to the
list of prerequisites that a target depends on.
However, if a target is multiply defined
only one definition may specify a recipe
for making the target.
When a target's rule operator is modified by a second ':' (:: for example) then this definition may not be the only definition with a recipe for the target. There may be other :: target definition lines that specify a different set of prerequisites with a different recipe for updating the target. Any such target is made if any of the definitions find it to be out of date with respect to the related prerequisites and the corresponding recipe is used to update the target. By definition all '::' recipes that are found to be out of date for are executed.
In the following simple example, each rule has a `::' ruleop. In such an operator we call the first `:' the operator, and the second `:' the modifier.
a.o :: a.c b.h first recipe for making a.o a.o :: a.y b.h second recipe for making a.o
If a.o is found to be out of date with respect to a.c then the first recipe is used to make a.o. If it is found out of date with respect to a.y then the second recipe is used. If a.o is out of date with respect to b.h then both recipes are invoked to make a.o. In the last case the order of invocation corresponds to the order in which the rule definitions appear in the makefile.
- |
-
Is defined only for PERCENT rule target definitions. When specified it
indicates that the following construct should be parsed using the old
semantinc meaning:
%.o :| %.c %.r %.f ; some rule is equivalent to: %.o : %.c ; some rule %.o : %.r ; some rule %.o : %.f ; some rule
Targets defined using a single `:' operator with a recipe may be redefined again with a new recipe by using a `:' operator with a `:' modifier. This is equivalent to a target having been initially defined with a rule using a `:' modifier. Once a target is defined using a `:' modifier it may not be defined again with a recipe using only the `:' operator with no `:' modifier. In both cases the use of a `:' modifier creates a new list of prerequisites and makes it the current prerequisite list for the target. The `:' operator with no recipe always modifies the current list of prerequisites. Thus assuming each of the following definitions has a recipe attached, then:
-
joe : fred ... (1) joe :: more ... (2) and joe :: fred ... (3) joe :: more ... (4)
-
joe :: fred ... (5) joe : more ... (6) and joe : fred ... (7) joe : more ... (8)
prerequisites is a possibly empty list of targets that must be brought up to date before making the current target.
recipe is a short form and allows the user to specify short rule definitions on a single line. It is taken to be the first recipe line in a larger recipe if additional lines follow the rule definition. If the semi-colon is present but the recipe line is empty (ie. null string) then it is taken to be an empty rule. Any target so defined causes the Don't know how to make ... error message to be suppressed when dmake tries to make the target and fails. This silence is maintained for rules that are terminated by a semicolon and have no following recipe lines, for targets listed on the command line, for the first target found in the makefile, and for any target having no recipe but containing a list of prerequisites (see the COMPATIBILITY section for an exception to this rule if the AUGMAKE (-A) flag was specified.
RECIPES
The traditional format used by most versions of Make defines the recipe lines as arbitrary strings that may contain macro expansions. They follow a rule definition line and may be spaced apart by comment or blank lines. The list of recipe lines defining the recipe is terminated by a new target definition, a macro definition, or end-of-file. Each recipe line MUST begin with a <TAB> character which may optionally be followed with one or all of the characters '@%+-'. The '-' indicates that non-zero exit values (ie. errors) are to be ignored when this recipe line is executed, the '+' indicates that the current recipe line is to be executed using the shell, the '%' indicates that dmake should swap itself out to secondary storage (MSDOS only) before running the recipe and the '@' indicates that the recipe line should NOT be echoed to the terminal prior to being executed. Each switch is off by default (ie. by default, errors are significant, commands are echoed, no swapping is done and a shell is used only if the recipe line contains a character found in the value of the SHELLMETAS macro). Global settings activated via command line options or special attribute or target names may also affect these settings. An example recipe:
-
target : first recipe line second recipe line, executed independent of first. @a recipe line that is not echoed -and one that has errors ignored %and one that causes dmake to swap out +and one that is executed using a shell.
The second and new format of the recipe block begins the block with the character '[' (the open group character) in the last non-white space position of a line, and terminates the block with the character ']' (the close group character) in the first non-white space position of a line. In this form each recipe line need not have a leading TAB. This is called a recipe group. Groups so defined are fed intact as a single unit to a shell for execution whenever the corresponding target needs to be updated. If the open group character '[' is preceded by one or all of -, @ or % then they apply to the entire group in the same way that they apply to single recipe lines. You may also specify '+' but it is redundant as a shell is already being used to run the recipe. See the MAKING TARGETS section for a description of how dmake invokes recipes. Here is an example of a group recipe:
-
target : [ first recipe line second recipe line tall of these recipe lines are fed to a single copy of a shell for execution. ]
TEXT DIVERSIONS
dmake supports the notion of text diversions. If a recipe line contains the macro expression-
$(mktmp[,[file][,text]] data)
data can be any text and must be separated from the 'mktmp' portion of the macro name by white-space. The only restriction on the data text is that it must contain a balanced number of parentheses of the same kind as are used to initiate the $(mktmp ...) expression. For example:
-
$(mktmp $(XXX))
-
$(mktmp text (to dump to file)
-
${mktmp text (to dump to file}
-
mytext:=this is a\ntest of the text diversion all: cat $(mktmp $(mytext:m))
-
cat /tmp/mk12294AA
-
OBJ = fred.obj mary.obj joe.obj all : $(OBJ) link @$(mktmp $(^:t"+\n"))
-
link @/tmp/mk02394AA
-
fred.obj+ mary.obj+ joe.obj
If the optional file specifier is present then its expanded value is the name of the temporary file to create. An example that would be useful for MSDOS users with a Turbo-C compiler
-
$(mktmp,turboc.cfg $(CFLAGS))
Under MS-DOS text diversions may be a problem. Many DOS tools require that path names which contain directories use the \ character to delimit the directories. Some users however wish to use the '/' to delimit pathnames and use environments that allow them to do so. The macro USESHELL is set to "yes" if the current recipe is forced to use a shell via the .USESHELL or '+' directives, otherwise its value is "no". The dmake startup files define the macro DIVFILE whose value is either the value of TMPFILE or the value of TMPFILE edited to replace any '/' characters to the appropriate value based on the current shell and whether it will be used to execute the recipe.
Previous versions of dmake defined text diversions using <+, +> strings, where <+ started a text diversion and +> terminated one. dmake is backward compatible with this construct only if the <+ and +> appear literally on the same recipe line or in the same macro value string. In such instances the expression:
<+data+>
is mapped to:
$(mktmp data)
which is fully output compatible with the earlier construct. <+, +> constructs whose text spans multiple lines must be converted by hand to use $(mktmp ...).
If the environment variable TMPDIR is defined then the temporary file is placed into the directory specified by that variable. A makefile can modify the location of temporary files by defining a macro named TMPDIR and exporting it using the .EXPORT special target.
SPECIAL TARGETS
This section describes the special targets that are recognized by dmake. Some are affected by attributes and others are not.- .ERROR
- If defined then the recipe associated with this target is executed whenever an error condition is detected by dmake. All attributes that can be used with any other target may be used with this target. Any prerequisites of this target will be brought up to date during its processing. NOTE: errors will be ignored while making this target, in extreme cases this may cause some problems.
- .EXIT
- If this target is encountered while parsing a makefile then the parsing of the makefile is immediately terminated at that point.
- .EXPORT
-
All prerequisites associated with this target are assumed to
correspond to macro names and they and their values
are exported to the environment as environment strings at the point in
the makefile at which this target appears.
Any attributes specified with this target are ignored.
Only macros which have been assigned a value in the makefile prior to the
export directive are exported, macros as yet undefined
or macros whose value contains any of the characters "+=:*"
are not exported.
Note that macros that are not expanded during the macro assignment and contain other macros will be written into the environment containing these other macros in the form of $(macroname).
- .IMPORT
- Prerequisite names specified for this target are searched for in the environment and defined as macros with their value taken from the environment. If the special name .EVERYTHING is used as a prerequisite name then all environment variables defined in the environment are imported. The functionality of the -E flag can be forced by placing the construct .IMPORT : .EVERYTHING at the start of a makefile. Similarly, by placing the construct at the end, one can emulate the effect of the -e command line flag. If a prerequisite name cannot be found in the environment an error message is issued. .IMPORT accepts the .IGNORE attribute. When given, it causes dmake to ignore the above error. See the MACROS section for a description of the processing of imported macro values.
- .INCLUDE
- Parse another makefile just as if it had been located at the point of the .INCLUDE in the current makefile. The list of prerequisites gives the list of makefiles to try to read. If the list contains multiple makefiles then they are read in order from left to right. The following search rules are used when trying to locate the file. If the filename is surrounded by " or just by itself then it is searched for in the current directory. If it is not found it is then searched for in each of the directories specified as prerequisites of the .INCLUDEDIRS special target. If the file name is surrounded by < and >, (ie. <my_spiffy_new_makefile>) then it is searched for only in the directories given by the .INCLUDEDIRS special target. In both cases if the file name is a fully qualified name starting at the root of the file system then it is only searched for once, and the .INCLUDEDIRS list is ignored. If .INCLUDE fails to find the file it invokes the inference engine to try to infer and hence make the file to be included. In this way the file can be checked out of an RCS repository for example. .INCLUDE accepts the .IGNORE, .SETDIR, and .NOINFER attributes. If the .IGNORE attribute is given and the file cannot be found then dmake continues processing, otherwise an error message is generated. If the .NOINFER attribute is given and the file cannot be found then dmake will not attempt to infer and make the file. The .SETDIR attribute causes dmake to change directories to the specified directory prior to attempting the include operation. If all fails dmake attempts to make the file to be included. If making the file fails then dmake terminates unless the .INCLUDE directive also specified the .IGNORE attribute. If .FIRST is specified along with .INCLUDE then dmake attempts to include each named prerequisite and will terminate the inclusion with the first prerequisite that results in a successful inclusion.
- .INCLUDEDIRS
- The list of prerequisites specified for this target defines the set of directories to search when trying to include a makefile.
- .KEEP_STATE
-
This special target is a synonym for the macro definition
.KEEP_STATE := _state.mk
It's effect is to turn on STATE keeping and to define _state.mk as the state file.
- .MAKEFILES
-
The list of prerequisites is the set of files to try to read as the default
makefile. By default this target is defined as:
.MAKEFILES : makefile.mk Makefile makefile
- .SOURCE
- The prerequisite list of this target defines a set of directories to check when trying to locate a target file name. See the section on BINDING of targets for more information.
- .SOURCE.suff
- The same as .SOURCE, except that the .SOURCE.suff list is searched first when trying to locate a file matching the a target whose name ends in the suffix .suff.
- .REMOVE
- The recipe of this target is used whenever dmake needs to remove intermediate targets that were made but do not need to be kept around. Such targets result from the application of transitive closure on the dependency graph.
In addition to the special targets above, several other forms of targets are recognized and are considered special, their exact form and use is defined in the sections that follow.
SPECIAL MACROS
dmake defines a number of special macros. They are divided into three classes: control macros, run-time macros, and function macros. The control macros are used by dmake to configure its actions, and are the preferred method of doing so. In the case when a control macro has the same function as a special target or attribute they share the same name as the special target or attribute. The run-time macros are defined when dmake makes targets and may be used by the user inside recipes. The function macros provide higher level functions dealing with macro expansion and diversion file processing.CONTROL MACROS
To use the control macros simply assign them a value just like any other macro. The control macros are divided into three groups: string valued macros, character valued macros, and boolean valued macros.The following are all of the string valued macros. This list is divided into two groups. The first group gives the string valued macros that are defined internally and cannot be directly set by the user.
- ABSMAKECMD
-
Warning! This macro's value is differently defined for a native Windows
dmake executable (compiled with MS Visual C++ or MinGW) and dmake for other
operating systems or build with other compilers.
In the first case its value is the absolute filename of the executable of the current dmake process, otherwise it is defined as the NULL string.
- INCDEPTH
- This macro's value is a string of digits representing the current depth of makefile inclusion. In the first makefile level this value is zero.
- MFLAGS
- Is the list of flags that were given on the command line including a leading switch character. The -f flag is not included in this list.
- MAKECMD
- Is the name with which dmake was invoked.
- MAKEDIR
- Is the full path to the initial directory in which dmake was invoked.
- MAKEFILE
- Contains the string "-f makefile" where, makefile is the name of initial user makefile that was first read.
- MAKEFLAGS
- Is the same as $(MFLAGS) but has no leading switch character. (ie. MFLAGS = -$(MAKEFLAGS))
- MAKEMACROS
- Contains the complete list of macro expressions that were specified on the command line.
- MAKETARGETS
- Contains the name(s) of the target(s), if any, that were specified on the command line.
- MAKEVERSION
- Contains a string indicating the current dmake version number.
- MAXPROCESSLIMIT
- Is a numeric string representing the maximum number of processes that dmake can use when making targets using parallel mode.
- NULL
- Is permanently defined to be the NULL string. This is useful when comparing a conditional expression to an NULL value.
- PWD
- Is the full path to the current directory in which make is executing.
- SPACECHAR
- Is permanently defined to contain one space character. This is useful when using space characters in function macros, e.g. subst, that otherwise would get deleted (leading/trailing spaces) or for using spaces in function macro parameters.
- TMPFILE
- Is set to the name of the most recent temporary file opened by dmake. Temporary files are used for text diversions and for group recipe processing.
- TMD
- Stands for "To Make Dir", and is the path from the present directory (value of $(PWD)) to the directory that dmake was started up in (value of $(MAKEDIR)). If the present directory is the directory that dmake was started up in TMD will be set to the relative path ".". This allows to create valid paths by prepending $(TMD)$(DIRSEPSTR) to a relative path. This macro is modified when .SETDIR attributes are processed.
- USESHELL
-
The value of this macro is set to "yes" if the current recipe is forced to
use a shell for its execution via the .USESHELL or '+' directives, its value
is "no" otherwise.
The second group of string valued macros control dmake behavior and may be set by the user.
- .DIRCACHE
- If set to "yes" enables the directory cache (this is the default). If set to "no" disables the directory cache (equivalent to -d command-line flag).
- .DIRCACHERESPCASE
- If set to "yes" causes the directory cache, if enabled, to respect file case, if set to "no" facilities of the native OS are used to match file case.
- NAMEMAX
- Defines the maximum length of a filename component. The value of the variable is initialized at startup to the value of the compiled macro NAME_MAX. On some systems the value of NAME_MAX is too short by default. Setting a new value for NAMEMAX will override the compiled value.
- .NOTABS
- When set to "yes" enables the use of spaces as well as <tabs> to begin recipe lines. By default a non-group recipe is terminated by a line without any leading white-space or by a line not beggining with a <tab> character. Enabling this mode modifies the first condition of the above termination rule to terminate a non-group recipe with a line that contains only white-space. This mode does not effect the parsing of group recipes bracketed by [].
- AUGMAKE
- If set to "yes" value will enable the transformation of special meta targets to support special AUGMAKE inferences (See the COMPATIBILITY section).
- DIRBRKSTR
- Contains the string of chars used to terminate the name of a directory in a pathname. Under UNIX its value is "/", under MSDOS its value is "/\:".
- DIRSEPSTR
- Contains the string that is used to separate directory components when path names are constructed. It is defined with a default value at startup.
- DIVFILE
- Is defined in the startup file and gives the name that should be returned for the diversion file name when used in $(mktmp ...) expansions, see the TEXT DIVERSION section for details.
- DYNAMICNESTINGLEVEL
- Specifies the maximum number of recursive dynamic macro expansions. Its initial value is 100.
- .KEEP_STATE
- Assigning this macro a value tells dmake the name of the state file to use and turns on the keeping of state information for any targets that are brought up to date by the make.
- GROUPFLAGS
- This macro gives the set of flags to pass to the shell when invoking it to execute a group recipe. The value of the macro is the list of flags with a leading switch indicator. (ie. `-' under UNIX)
- GROUPSHELL
- This macro defines the full path to the executable image to be used as the shell when processing group recipes. This macro must be defined if group recipes are used. It is assigned a default value in the startup makefile. Under UNIX this value is /bin/sh.
- GROUPSUFFIX
- If defined, this macro gives the string to use as a suffix when creating group recipe files to be handed to the command interpreter. For example, if it is defined as .sh, then all temporary files created by dmake will end in the suffix .sh. Under MSDOS if you are using command.com as your GROUPSHELL, then this suffix must be set to .bat in order for group recipes to function correctly. The setting of GROUPSUFFIX and GROUPSHELL is done automatically for command.com in the startup.mk files.
- MAKE
- Is defined in the startup file by default. Initially this macro is defined to have the value "$(MAKECMD) $(MFLAGS)". The string $(MAKE) is recognized when using the -n switch.
- MAKESTARTUP
- This macro defines the full path to the initial startup makefile. Use the -V command line option to discover its initial value.
- MAXLINELENGTH
- This macro defines the maximum size of a single line of makefile input text. The size is specified as a number, the default value is defined internally and is shown via the -V option. A buffer of this size plus 2 is allocated for reading makefile text. The buffer is freed before any targets are made, thereby allowing files containing long input lines to be processed without consuming memory during the actual make. This macro can only be used to extend the line length beyond it's default minimum value.
- MAXPROCESS
- Specify the maximum number of child processes to use when making targets. The default value of this macro is "1" and its value cannot exceed the value of the macro MAXPROCESSLIMIT. Setting the value of MAXPROCESS on the command line or in the makefile is equivalent to supplying a corresponding value to the -P flag on the command line.
- PREP
-
This macro defines the number of iterations to be expanded
automatically when processing % rule definitions of the form:
% : %.suff
See the sections on PERCENT(%) RULES for details on how PREP is used.
- SHELL
- This macro defines the full path to the executable image to be used as the shell when processing single line recipes. This macro must be defined if recipes requiring the shell for execution are to be used. It is assigned a default value in the startup makefile. Under UNIX this value is /bin/sh.
- SHELLFLAGS
- This macro gives the set of flags to pass to the shell when invoking it to execute a single line recipe. The value of the macro is the list of flags with a leading switch indicator. (ie. `-' under UNIX)
- SHELLMETAS
-
Each time
dmake
executes a single recipe line (not a group recipe) the line is
searched for any occurrence of a character defined in the value of SHELLMETAS.
If such a character is found the recipe line is defined to require a shell
to ensure its correct execution. In such instances
a shell is used to invoke the recipe line.
If no match is found the recipe line is executed without the use of a shell.
There is only one character valued macro defined by dmake: SWITCHAR contains the switch character used to introduce options on command lines. For UNIX its value is `-', and for MSDOS its value may be `/' or `-'. The macro is internally defined and is not user setable. The MSDOS version of dmake attempts to first extract SWITCHAR from an environment variable of the same name. If that fails it then attempts to use the undocumented getswitchar system call, and returns the result of that. Under MSDOS version 4.0 you must set the value of the environment macro SWITCHAR to '/' to obtain predictable behavior.
All boolean macros currently understood by dmake correspond directly to the previously defined attributes. These macros provide a second way to apply global attributes, and represent the preferred method of doing so. They are used by assigning them a value. If the value is not a NULL string then the boolean condition is set to on. If the value is a NULL string then the condition is set to off. There are five conditions defined and they correspond directly to the attributes of the same name. Their meanings are defined in the ATTRIBUTES section above. The macros are: .EPILOG, .IGNORE, .MKSARGS, .NOINFER, .PRECIOUS, .PROLOG, .SEQUENTIAL, .SILENT, .SWAP, and .USESHELL. Assigning any of these a non NULL value will globally set the corresponding attribute to on.
RUNTIME MACROS
These macros are defined when dmake is making targets, and may take on different values for each target. $@ is defined to be the full target name, $? is the list of all out of date prerequisites, $& is the list of all prerequisites, $> is the name of the library if the current target is a library member, and $< is the list of prerequisites specified in the current rule. If the current target had a recipe inferred then $< is the name of the inferred prerequisite even if the target had a list of prerequisites supplied using an explicit rule that did not provide a recipe. In such situations $& gives the full list of prerequisites.$* is defined as $(@:db) when making targets with explicit recipes and is defined as the value of % when making targets whose recipe is the result of an inference. In the first case $* is the target name with no suffix, and in the second case, is the value of the matched % pattern from the associated %-rule. $^ expands to the set of out of date prerequisites taken from the current value of $<. In addition to these, $$ expands to $, {{ expands to {, }} expands to }, and the strings <+ and +> are recognized as respectively starting and terminating a text diversion when they appear literally together in the same input line.
The difference between $? and $^ can best be illustrated by an example, consider:
-
fred.out : joe amy hello rules for making fred fred.out : my.c your.h his.h her.h # more prerequisites
-
- $@
- --> fred.out
- $*
- --> fred
- $?
- --> joe amy my.c # note output of $? vs $^
- $^
- --> joe amy
- $<
- --> joe amy hello
- $&
- --> joe amy hello my.c your.h his.h her.h
FUNCTION MACROS
dmake supports a full set of functional macros. One of these, the $(mktmp ...) macro, is discussed in detail in the TEXT DIVERSION section and is not covered here.Note that some of these macros take comma separated parameters but that these parameters must not contain literal whitespaces. Whitespaces in macros used in these parameters are allowed.
-
- $(and macroterm ...)
-
expands each macroterm in turn until there are no more or one of
them returns an empty string. If all expand to non-empty strings the
macro returs the string "t" otherwise it returns an empty string.
- $(assign expression)
-
Causes expression to be parsed as a macro assignment expression and results
in the specified assignment being made. An error is issued if the assignment
is not syntatically correct. expression may contain white space. This is
in effect a dynamic macro assignment facility and may appear anywhere any
other macro may appear. The result of the expanding a dynamic macro
assignment expression is the name of the macro that was assigned and $(NULL)
if the expression is not a valid macro assignment expression.
Some examples are:
-
$(assign foo := fred) $(assign $(ind_macro_name) +:= $(morejunk))
-
- $(echo list)
- Echo's the value of list. list is not expanded.
- $(eq,text_a,text_b true false)
- expands text_a and text_b and compares their results. If equal it returns the result of the expansion of the true term, otherwise it returns the expansion of the false term.
- $(!eq,text_a,text_b true false)
- Behaves identically to the previous macro except that the true string is chosen if the expansions of the two strings are not equal
- $(foreach,var,list data)
-
Implements iterative macro expansion over data using var as the
iterator taking on values from list. var and list are
expanded and the result is the concatenation of expanding data with
var being set to each whitespace separated token from list.
For example:
-
-
list = a b c all :; echo [$(foreach,i,$(list) [$i])]
-
[[a] [b] [c]]
-
$(foreach,i,$(foreach,i,$(sort c a b) root/$i) [$i/f.h])
-
[root/a/f.h] [root/b/f.h] [root/c/f.h]
-
$($(assign list=a b c)) $(sort d a b c) $(echo a b c)
-
$(foreach,i,a b c [$i])
-
"b c [a]"
-
-
- $(nil expression)
- Always returns the value of $(NULL) regardless of what expression is. This function macro can be used to discard results of expanding macro expressions.
- $(not macroterm)
- expands macroterm and returs the string "t" if the result of the expansion is the empty string; otherwise, it returns the empty string.
- $(null,text true false)
- expands the value of text. If it is NULL then the macro returns the value of the expansion of true and the expansion of false otherwise. The terms true, and false must be strings containing no white-space.
- $(!null,text true false)
- Behaves identically to the previous macro except that the true string is chosen if the expansion of text is not NULL.
- $(or macroterm ...)
- expands each macroterm in turn and returs the empty string if each term expands to the empty string; otherwise, it returs the string "t".
- $(shell command)
-
is a shell escape macro. It runs command as if it were part of a
recipe and returns, separated by a single space, all the non-white
space terms written to stdout by the command.
For example:
-
-
$(shell ls *.c)
-
$(shell +ls *.c)
Note that if the macro is part of a recipe it will be evaluated after all previous recipe lines have been executed. For obvious reasons it will be evaluated before the current recipe line or group recipe is executed.
-
-
- $(shell,expand command)
- Is an extension to the $(shell command) function macro that expands the result of running command.
- $(sort list)
- Will take all white-space separated tokens in list and will return their sorted equivalent list.
- $(strip data)
- Will replace all strings of white-space in data by a single space.
- $(subst,pat,replacement data)
-
Will search for pat in
data
and will replace any occurrence of
pat
with the
replacement
string. The expansion
-
$(subst,.o,.c $(OBJECTS))
-
$(OBJECTS:s/.o/.c/)
-
- $(uniq list)
- Will take all white-space separated tokens in list and will return their sorted equivalent list containing no duplicates.
CONDITIONAL MACROS
dmake supports conditional macros. These allow the definition of target specific macro values. You can now say the following:-
target ?= MacroName MacroOp Value
The new definition is associated with the most recent cell definition for target. If no prior definition exists then one is created. The implications of this are immediately evident in the following example:
-
foo := hello all : cond;@echo "all done, foo=[$(foo)] bar=[$(bar)]" cond ?= bar := global decl cond .SETDIR=unix::;@echo $(foo) $(bar) cond ?= foo := hi cond .SETDIR=msdos::;@echo $(foo) $(bar) cond ?= foo := hihi
The first conditional assignment creates a binding for 'bar' that is activated when 'cond' is made. The bindings following the :: definitions are activated when their respective recipe rules are used. Thus the first binding serves to provide a global value for 'bar' while any of the cond :: rules are processed, and the local bindings for 'foo' come into effect when their associated :: rule is processed.
Conditionals for targets of .UPDATEALL are all activated before the target group is made. Assignments are processed in order. Note that the value of a conditional macro assignment is NOT AVAILABLE until the associated target is made, thus the construct
-
mytarget ?= bar := hello mytarget ?= foo := $(bar)
results in $(foo) expanding to "", if you want the result to be "hello" you must use:
-
mytarget ?= bar := hello mytarget ?= foo = $(bar)
Once a target is made any associated conditional macros are deactivated and their values are no longer available. Activation occurrs after all inference, and .SETDIR directives have been processed and after $@ is assigned, but before prerequisites are processed; thereby making the values of conditional macro definitions available during construction of prerequisites.
If a %-meta rule target has associated conditional macro assignments, and the rule is chosen by the inference algorithm then the conditional macro assignments are inferred together with the associated recipe.
DYNAMIC PREREQUISITES
dmake looks for prerequisites whose names contain macro expansions during target processing. Any such prerequisites are expanded and the result of the expansion is used as the prerequisite name. As an example the line:fred : $$@.c
causes the $$@ to be expanded when dmake is making fred, and it resolves to the target fred. This enables dynamic prerequisites to be generated. The value of @ may be modified by any of the valid macro modifiers. So you can say for example:
fred.out : $$(@:b).c
where the $$(@:b) expands to fred. Note the use of $$ instead of $ to indicate the dynamic expansion, this is due to the fact that the rule line is expanded when it is initially parsed, and $$ then returns $ which later triggers the dynamic prerequisite expansion. If you really want a $ to be part of a prerequisite name you must use $$$$. Dynamic macro expansion is performed in all user defined rules, and the special targets .SOURCE*, and .INCLUDEDIRS.
If dynamic macro expansion results in multiple white space separated tokens then these are inserted into the prerequisite list inplace of the dynamic prerequisite. If the new list contains additional dynamic prerequisites they will be expanded when they are processed. The level of recursion in this expansion is controlled by the value of the variable DYNAMICNESTINGLEVEL and is set to 100 by default.
BINDING TARGETS
This operation takes a target name and binds it to an existing file, if possible. dmake makes a distinction between the internal target name of a target and its associated external file name. Thus it is possible for a target's internal name and its external file name to differ. To perform the binding, the following set of rules is used. Assume that we are trying to bind a target whose name is of the form X.suff, where .suff is the suffix and X is the stem portion (ie. that part which contains the directory and the basename). dmake takes this target name and performs a series of search operations that try to find a suitably named file in the external file system. The search operation is user controlled via the settings of the various .SOURCE targets.-
- 1.
- If target has the .SYMBOL attribute set then look for it in the library. If found, replace the target name with the library member name and continue with step 2. If the name is not found then return.
- 2.
- Extract the suffix portion (that following the `.') of the target name. If the suffix is not null, look up the special target .SOURCE.<suff> (<suff> is the suffix). If the special target exists then search each directory given in the .SOURCE.<suff> prerequisite list for the target. If the target's suffix was null (ie. .suff was empty) then perform the above search but use the special target .SOURCE.NULL instead. If at any point a match is found then terminate the search. If a directory in the prerequisite list is the special name `.NULL ' perform a search for the full target name without prepending any directory portion (ie. prepend the NULL directory).
- 3.
- The search in step 2. failed. Repeat the same search but this time use the special target .SOURCE. (a default target of '.SOURCE : .NULL' is defined by dmake at startup, and is user redefinable)
- 4.
- The search in step 3. failed. If the target has the library member attribute (.LIBMEMBER) set then try to find the target in the library which was passed along with the .LIBMEMBER attribute (see the MAKING LIBRARIES section). The bound file name assigned to a target which is successfully located in a library is the same name that would be assigned had the search failed (see 5.).
- 5.
- The search failed. Either the target was not found in any of the search directories or no applicable .SOURCE special targets exist. If applicable .SOURCE special targets exist, but the target was not found, then dmake assigns the first name searched as the bound file name. If no applicable .SOURCE special targets exist, then the full original target name becomes the bound file name.
There is potential here for a lot of search operations. The trick is to define .SOURCE.x special targets with short search lists and leave .SOURCE as short as possible. The search algorithm has the following useful side effect. When a target having the .LIBMEMBER (library member) attribute is searched for, it is first searched for as an ordinary file. When a number of library members require updating it is desirable to compile all of them first and to update the library at the end in a single operation. If one of the members does not compile and dmake stops, then the user may fix the error and make again. dmake will not remake any of the targets whose object files have already been generated as long as none of their prerequisite files have been modified as a result of the fix.
When dmake constructs target pathnames './' substrings are removed and substrings of the form 'foo/..' are eliminated. This may result in somewhat unexpected values of the macro expansion $@, but is infact the corect result.
When defining .SOURCE and .SOURCE.x targets the construct
dmake correctly handles the UNIX Make variable VPATH. By definition VPATH contains a list of ':' separated directories to search when looking for a target. dmake maps VPATH to the following special rule:
PERCENT(%) RULES AND MAKING INFERENCES
When dmake makes a target, the target's set of prerequisites (if any) must exist and the target must have a recipe which dmake can use to make it. If the makefile does not specify an explicit recipe for the target then dmake uses special rules to try to infer a recipe which it can use to make the target. Previous versions of Make perform this task by using rules that are defined by targets of the form .<suffix>.<suffix> and by using the .SUFFIXES list of suffixes. The exact workings of this mechanism were sometimes difficult to understand and often limiting in their usefulness. Instead, dmake supports the concept of %-meta rules. The syntax and semantics of these rules differ from standard rule lines as follows:
- <%-target> [<attributes>] <ruleop> [<%-prerequisites>] [;<recipe>]
where %-target is a target containing exactly a single `%' sign, attributes is a list (possibly empty) of attributes, ruleop is the standard set of rule operators, %-prerequisites , if present, is a list of prerequisites containing zero or more `%' signs, and recipe, if present, is the first line of the recipe.
The %-target defines a pattern against which a target whose recipe is being inferred gets matched. The pattern match goes as follows: all chars are matched exactly from left to right up to but not including the % sign in the pattern, % then matches the longest string from the actual target name not ending in the suffix given after the % sign in the pattern. Consider the following examples:
-
- %.c
- matches fred.c but not joe.c.Z
- dir/%.c
- matches dir/fred.c but not dd/fred.c
- fred/%
- matches fred/joe.c but not f/joe.c
- %
- matches anything
-
%.c : %.y ; recipe...
-
foo%.o : fee%.k ; recipe...
-
%.a :; recipe...
-
%.c : %.y yaccsrc/%.y ; recipe...
-
%.c : %.y ; recipe...
%.c : yaccsrc/%.y ; recipe...
-
% : RCS/%,v ; co $<
-
% : s.% ; get $<
The previous RCS example defines an infinite rule, because it says how to make anything from RCS/%,v, and anything also includes RCS/fred.c,v. To limit the size of the graph that results from such rules dmake uses the macro variable PREP (stands for % repetition). By default the value of this variable is 0, which says that no repetitions of a %-rule are to be generated. If it is set to something greater than 0, then that many repetitions of any infinite %-rule are allowed. If in the above example PREP was set to 1, then dmake would generate the dependency graph:
-
% --> RCS/%,v --> RCS/RCS/%,v,v
dmake supports dynamic prerequisite generation for prerequisites of %-meta rules. This is best illustrated by an example. The RCS rule shown above can infer how to check out a file from a corresponding RCS file only if the target is a simple file name with no directory information. That is, the above rule can infer how to find RCS/fred.c,v from the target fred.c, but cannot infer how to find srcdir/RCS/fred.c,v from srcdir/fred.c because the above rule will cause dmake to look for RCS/srcdir/fred.c,v; which does not exist (assume that srcdir has its own RCS directory as is the common case).
A more versatile formulation of the above RCS check out rule is the following:
-
% : $$(@:d)RCS/$$(@:f),v : co $@
dmake can also infer indirect prerequisites. An inferred target can have a list of prerequisites added that will not show up in the value of $< but will show up in the value of $? and $&. Indirect prerequisites are specified in an inference rule by quoting the prerequisite with single quotes. For example, if you had the explicit dependency:
-
fred.o : fred.c ; rule to make fred.o fred.o : local.h
-
%.o : %.c 'local.h' ; makes a .o from a .c
-
%.o : %.c '$(INC)/%.h' ; rule to make a .o from a .c
-
%.o : %.c %.f 'local.h'; recipe
-
%.o : %.c 'local.h' : recipe
-
%.o :| %.c %.f 'local.h'; recipe
-
%.o : %.c 'local.h' : recipe %.o : %.f 'local.h' : recipe
If any of the attributes .SETDIR, .EPILOG, .PROLOG, .SILENT, .USESHELL, .SWAP, .PRECIOUS, .LIBRARY, .NOSTATE and .IGNORE are given for a %-rule then when that rule is bound to a target as the result of an inference, the target's set of attributes is augmented by the attributes from the above set that are specified in the bound %-rule. Other attributes specified for %-meta rules are not inherited by the target. The .SETDIR attribute is treated in a special way. If the target already had a .SETDIR attribute set then dmake changes to that directory prior to performing the inference. During inference any .SETDIR attributes for the inferred prerequisite are honored. The directories must exist for a %-meta rule to be selected as a possible inference path. If the directories do not exist no error message is issued, instead the corresponding path in the inference graph is rejected.
dmake also supports the old format special target .<suffix>.<suffix> by identifying any rules of this form and mapping them to the appropriate %-rule. So for example if an old makefile contains the construct:
-
.c.o :; cc -c $< -o $@
-
%.o : %.c; cc -c $< -o $@
-
.suff :; recipe
-
% : %.suff; recipe
-
.c~.o :; recipe
-
%.o : s.%.c ; recipe
dmake bases all of its inferences on the inference graph constructed from the %-rules defined in the makefile. It knows exactly which targets can be made from which prerequisites by making queries on the inference graph. For this reason .SUFFIXES is not needed and is completely ignored.
For a %-meta rule to be inferred as the rule whose recipe will be used to make a target, the target's name must match the %-target pattern, and any inferred %-prerequisite must already exist or have an explicit recipe so that the prerequisite can be made. Without transitive closure on the inference graph the above rule describes precisely when an inference match terminates the search. If transitive closure is enabled (the usual case), and a prerequisite does not exist or cannot be made, then dmake invokes the inference algorithm recursively on the prerequisite to see if there is some way the prerequisite can be manufactured. For, if the prerequisite can be made then the current target can also be made using the current %-meta rule. This means that there is no longer a need to give a rule for making a .o from a .y if you have already given a rule for making a .o from a .c and a .c from a .y. In such cases dmake can infer how to make the .o from the .y via the intermediary .c and will remove the .c when the .o is made. Transitive closure can be disabled by giving the -T switch on the command line.
A word of caution. dmake bases its transitive closure on the %-meta rule targets. When it performs transitive closure it infers how to make a target from a prerequisite by performing a pattern match as if the potential prerequisite were a new target. The set of rules:
-
%.o : %.c :; rule for making .o from .c %.c : %.y :; rule for making .c from .y % : RCS/%,v :; check out of RCS file
-
.NOINFER : RCS/%,v
dmake tries to remove intermediate files resulting from transitive closure if the file is not marked as being PRECIOUS, or the -u flag was not given on the command line, and if the inferred intermediate did not previously exist. Intermediate targets that existed prior to being made are never removed. This is in keeping with the philosophy that dmake should never remove things from the file system that it did not add. If the special target .REMOVE is defined and has a recipe then dmake constructs a list of the intermediate files to be removed and makes them prerequisites of .REMOVE. It then makes .REMOVE thereby removing the prerequisites if the recipe of .REMOVE says to. Typically .REMOVE is defined in the startup file as:
-
.REMOVE :; $(RM) $<
MAKING TARGETS
In order to update a target dmake must execute a recipe. When a recipe needs to be executed it is first expanded so that any macros in the recipe text are expanded, and it is then either executed directly or passed to a shell. dmake supports two types of recipes. The regular recipes and group recipes.When a regular recipe is invoked dmake executes each line of the recipe separately using a new copy of a shell if a shell is required. Thus effects of commands do not generally persist across recipe lines (e.g. cd requests in a recipe line do not carry over to the next recipe line). This is true even in environments such as MSDOS, where dmake internally sets the current working director to match the directory it was in before the command was executed.
The decision on whether a shell is required to execute a command is based on the value of the macro SHELLMETAS or on the specification of '+' or .USESHELL for the current recipe or target respectively. If any character in the value of SHELLMETAS is found in the expanded recipe text-line or the use of a shell is requested explicitly via '+' or .USESHELL then the command is executed using a shell, otherwise the command is executed directly. The shell that is used for execution is given by the value of the macro SHELL. The flags that are passed to the shell are given by the value of SHELLFLAGS. Thus dmake constructs the command line:
$(SHELL) $(SHELLFLAGS) $(expanded_recipe_command)
Normally dmake writes the command line that it is about to invoke to standard output. If the .SILENT attribute is set for the target or for the recipe line (via @), then the recipe line is not echoed.
Group recipe processing is similar to that of regular recipes, except that a shell is always invoked. The shell that is invoked is given by the value of the macro GROUPSHELL, and its flags are taken from the value of the macro GROUPFLAGS. If a target has the .PROLOG attribute set then dmake prepends to the shell script the recipe associated with the special target .GROUPPROLOG, and if the attribute .EPILOG is set as well, then the recipe associated with the special target .GROUPEPILOG is appended to the script file. This facility can be used to always prepend a common header and common trailer to group recipes. Group recipes are echoed to standard output just like standard recipes, but are enclosed by lines beginning with [ and ].
The recipe flags [+,-,%,@] are recognized at the start of a recipe line even if they appear in a macro. For example:
-
SH = + all: $(SH)echo hi
-
SH = + all: +echo hi
The last step performed by dmake prior to running a recipe is to set the macro CMNDNAME to the name of the command to execute (determined by finding the first white-space ending token in the command line). It then sets the macro CMNDARGS to be the remainder of the line. dmake then expands the macro COMMAND which by default is set to
-
COMMAND = $(CMNDNAME) $(CMNDARGS)
-
COMMAND = $(CMNDNAME) @$(mktmp $(CMNDARGS))
-
$(CMNDNAME) @/tmp/ASAD23043
MAKING LIBRARIES
Libraries are easy to maintain using dmake. A library is a file containing a collection of object files. Thus to make a library you simply specify it as a target with the .LIBRARY attribute set and specify its list of prerequisites. The prerequisites should be the object members that are to go into the library. When dmake makes the library target it uses the .LIBRARY attribute to pass to the prerequisites the .LIBMEMBER attribute and the name of the library. This enables the file binding mechanism to look for the member in the library if an appropriate object file cannot be found. dmake now supports Elf libraries on systems that support Elf and hence supports, on those systems, long member file names. A small example best illustrates this.-
mylib.a .LIBRARY : mem1.o mem2.o mem3.o rules for making library... # remember to remove .o's when lib is made # equivalent to: '%.o : %.c ; ...' .c.o :; rules for making .o from .c say
dmake tries to handle the old library construct format in a sensible way. The construct lib(member.o) is separated and the lib portion is declared as a library target. The new target is defined with the .LIBRARY attribute set and the member.o portion of the construct is declared as a prerequisite of the lib target. If the construct lib(member.o) appears as a prerequisite of a target in the makefile, that target has the new name of the lib assigned as its prerequisite. Thus the following example:
-
a.out : ml.a(a.o) ml.a(b.o); $(CC) -o $@ $< .c.o :; $(CC) -c $(CFLAGS) -o $@ $< %.a:
- ar rv $@ $? ranlib $@ rm -rf $?
-
a.out : ml.a; $(CC) -o $@ $< ml.a .LIBRARY : a.o b.o %.o : %.c ; $(CC) -c $(CFLAGS) -o $@ $< %.a :
- ar rv $@ $? ranlib $@ rm -rf $?
The same thing happens for any target of the form lib((entry)). These targets have an additional feature in that the entry target has the .SYMBOL attribute set automatically.
NOTE: If the notion of entry points is supported by the archive and by dmake (currently not the case) then dmake will search the archive for the entry point and return not only the modification time of the member which defines the entry but also the name of the member file. This name will then replace entry and will be used for making the member file. Once bound to an archive member the .SYMBOL attribute is removed from the target. This feature is presently disabled as there is little standardization among archive formats, and we have yet to find a makefile utilizing this feature (possibly due to the fact that it is unimplemented in most versions of UNIX Make).
Finally, when dmake looks for a library member it must first locate the library file. It does so by first looking for the library relative to the current directory and if it is not found it then looks relative to the current value of $(TMD). This allows commonly used libraries to be kept near the root of a source tree and to be easily found by dmake.
KEEP STATE
dmake supports the keeping of state information for targets that it makes whenever the macro .KEEP_STATE is assigned a value. The value of the macro should be the name of a state file that will contain the state information. If state keeping is enabled then each target that does not poses the .NOSTATE attribute will have a record written into the state file indicating the target's name, the current directory, the command used to update the target, and which, if any, :: rule is being used. When you make this target again if any of this information does not match the previous settings and the target is not out dated it will still be re-made. The assumption is that one of the conditions above has changed and that we wish to remake the target. For example, state keeping is used in the maintenance of dmake to test compile different versions of the source using different compilers. Changing the compiler causes the compilation flags to be modified and hence all sources to be recompiled.The state file is an ascii file and is portable, however it is not in human readable form as the entries represent hash keys of the above information.
The Sun Microsystem's Make construct
-
.KEEP_STATE :
MULTI PROCESSING
If the architecture supports it then dmake is capable of making a target's prerequisites in parallel. dmake will make as much in parallel as it can and use a number of child processes up to the maximum specified by MAXPROCESS or by the value supplied to the -P command line flag. A parallel make is enabled by setting the value of MAXPROCESS (either directly or via -P option) to a value which is > 1. dmake guarantees that all dependencies as specified in the makefile are honored. A target will not be made until all of its prerequisites have been made. Note that when you specify -P 4 then four child processes are run concurrently but dmake actually displays the fifth command it will run immediately upon a child process becomming free. This is an artifact of the method used to traverse the dependency graph and cannot be removed. If a parallel make is being performed then the following restrictions on parallelism are enforced.-
- 1.
- Individual recipe lines in a non-group recipe are performed sequentially in the order in which they are specified within the makefile and in parallel with the recipes of other targets.
- 2.
- If a target contains multiple recipe definitions (cf. :: rules) then these are performed sequentially in the order in which the :: rules are specified within the makefile and in parallel with the recipes of other targets.
- 3.
- If a target rule contains the `!' modifier, then the recipe is performed sequentially for the list of outdated prerequisites and in parallel with the recipes of other targets.
- 4.
- If a target has the .SEQUENTIAL attribute set then all of its prerequisites are made sequentially relative to one another (as if MAXPROCESS=1), but in parallel with other targets in the makefile.
Note: If you specify a parallel make then the order of target update and the order in which the associated recipes are invoked will not correspond to that displayed by the -n flag.
CONDITIONALS
dmake supports a makefile construct called a conditional. It allows the user to conditionally select portions of makefile text for input processing and to discard other portions. This becomes useful for writing makefiles that are intended to function for more than one target host and environment. The conditional expression is specified as follows:
-
.IF expression ... if text ... .ELIF expression ... if text ... .ELSE ... else text ... .END
The .ELSE and .ELIF portions are optional, and the conditionals may be nested (ie. the text may contain another conditional). .IF, .ELSE, and .END may appear anywhere in the makefile, but a single conditional expression may not span multiple makefiles.
expression can be one of the following forms:
String evaluation
<text> | <text> == <text> | <text> != <text>
Numeric evaluation
<text> <= <text> | <text> >= <text>
Boolean evaluation
( <text> ) | <text> || <text> | <text> && <text>
where text is either text or a macro expression. In any case, before the comparison is made, the expression is expanded. The text portions are then selected and compared. In the case of the numeric comparisons the expanded expressions are converted to an integer number. Expressions can be nested with () and the use of || or &&. White space at the start and end of the text portion is discarded before the comparison. This means that a macro that evaluates to nothing but white space is considered a NULL value for the purpose of the comparison. In the first case the expression evaluates TRUE if the text is not NULL otherwise it evaluates FALSE. The remaining two cases both evaluate the expression on the basis of a string comparison. If a macro expression needs to be equated to a NULL string then compare it to the value of the macro $(NULL). You can use the $(shell ...) macro to construct more complex test expressions.
EXAMPLES
-
# A simple example showing how to use make # prgm : a.o b.o cc a.o b.o -o prgm a.o : a.c g.h cc a.c -o $@ b.o : b.c g.h cc b.c -o $@
In the previous example prgm is remade only if a.o and/or b.o is out of date with respect to prgm. These dependencies can be stated more concisely by using the inference rules defined in the standard startup file. The default rule for making .o's from .c's looks something like this:
%.o : %.c; cc -c $(CFLAGS) -o $@ $<
Since there exists a rule (defined in the startup file) for making .o's from .c's dmake will use that rule for manufacturing a .o from a .c and we can specify our dependencies more concisely.
-
prgm : a.o b.o cc -o prgm $< a.o b.o : g.h
A more general way to say the above using the new macro expansions would be:
-
SRC = a b OBJ = {$(SRC)}.o prgm : $(OBJ) cc -o $@ $< $(OBJ) : g.h
If we want to keep the objects in a separate directory, called objdir, then we would write something like this.
-
SRC = a b OBJ = {$(SRC)}.o prgm : $(OBJ) cc $< -o $@ $(OBJ) : g.h %.o : %.c $(CC) -c $(CFLAGS) -o $(@:f) $< mv $(@:f) objdir .SOURCE.o : objdir # tell dmake to look here for .o's
An example of building library members would go something like this: (NOTE: The same rules as above will be used to produce .o's from .c's)
-
SRC = a b LIB = lib LIBm = { $(SRC) }.o prgm: $(LIB) cc -o $@ $(LIB) $(LIB) .LIBRARY : $(LIBm) ar rv $@ $< rm $<
Finally, suppose that each of the source files in the previous example had the `:' character in their target name. Then we would write the above example as:
-
SRC = f:a f:b LIB = lib LIBm = "{ $(SRC) }.o" # put quotes around each token prgm: $(LIB) cc -o $@ $(LIB) $(LIB) .LIBRARY : $(LIBm) ar rv $@ $< rm $<
COMPATIBILITY
There are two notable differences between dmake and the standard version of BSD UNIX 4.2/4.3 Make.-
- 1.
-
BSD UNIX 4.2/4.3 Make supports wild card filename expansion for
prerequisite names. Thus if a directory contains a.h, b.h and c.h, then a
line like
target: *.h
will cause UNIX make to expand the *.h into "a.h b.h c.h". dmake does not support this type of filename expansion.
- 2.
- Unlike UNIX make, touching a library member causes dmake to search the library for the member name and to update the library time stamp. This is only implemented in the UNIX version. MSDOS and other versions may not have librarians that keep file time stamps, as a result dmake touches the library file itself, and prints a warning.
dmake is not compatible with GNU Make. In particular it does not understand GNU Make's macro expansions that query the file system.
dmake is fully compatible with SYSV AUGMAKE, and supports the following AUGMAKE features:
-
- 1.
- GNU Make style include, and if/else/endif directives are allowed in non-group recipes. Thus, the word include appearing at the start of a line that is not part of a gruop recipe will be mapped to the ".INCLUDE" directive that damke uses. Similarly, the words ifeq,ifneq,elif,else, and endif are mapped to their corresponding dmake equivalents.
- 2.
-
The macro modifier expression $(macro:str=sub) is understood and is equivalent
to the expression $(macro:s/str/sub), with the restriction that str must match
the following regular expression:
str[ |\t][ |\t]*
(ie. str only matches at the end of a token where str is a suffix and is terminated by a space, a tab, or end of line) Normally sub is expanded before the substitution is made, if you specify -A on the command line then sub is not expanded.
- 3.
- The macro % is defined to be $@ (ie. $% expands to the same value as $@).
- 4.
- The AUGMAKE notion of libraries is handled correctly.
- 5.
- When defining special targets for the inference rules and the AUGMAKE special target handling is enabled then the special target .X is equivalent to the %-rule "% : %.X".
- 6.
- Directories are always made if you specify -A. This is consistent with other UNIX versions of Make.
- 7.
-
Makefiles that utilize virtual targets to force making of other targets work
as expected if AUGMAKE special target handling is enabled. For example:
FRC: myprog.o : myprog.c $(FRC) ; ...
Works as expected if you issue the command
'dmake -A FRC=FRC'
but fails with a 'don't know how to make FRC' error message if you do not specify AUGMAKE special target handling via the -A flag (or by setting AUGMAKE:=yes internally).
- 8.
- The MSDOS version of dmake now supports a single buitin runtime command noop, which returns success if requested and does nothing.
LIMITS
In some environments the length of an argument string is restricted. (e.g. MSDOS command line arguments cannot be longer than 128 bytes if you are using the standard command.com command interpreter as your shell, dmake text diversions may help in these situations.)PORTABILITY
To write makefiles that can be moved from one environment to another requires some forethought. In particular you must define as macros all those things that may be different in the new environment. dmake has two facilities that help to support writing portable makefiles, recursive macros and conditional expressions. The recursive macros, allow one to define environment configurations that allow different environments for similar types of operating systems. For example the same make script can be used for SYSV and BSD but with different macro definitions.To write a makefile that is portable between UNIX and MSDOS requires both features since in almost all cases you will need to define new recipes for making targets. The recipes will probably be quite different since the capabilities of the tools on each machine are different. Different macros will be needed to help handle the smaller differences in the two environments.
FILES
Makefile, makefile, startup.mk (use dmake -V to tell you where the startup file is)SEE ALSO
sh(1), csh(1), touch(1), f77(1), pc(1), cc(1)S.I. Feldman Make - A Program for Maintaining Computer Programs
AUTHOR
Dennis Vadura, dvadura@wticorp.comMany thanks to Carl Seger for his helpful suggestions, and to Trevor John Thompson for his many excellent ideas and informative bug reports. Many thanks also go to those on the NET that have helped in making dmake one of the best Make tools available.
BUGS
Some system commands return non-zero status inappropriately. Use -i (`-' within the makefile) to overcome the difficulty.Some systems do not have easily accessible time stamps for library members (MSDOS, AMIGA, etc) for these dmake uses the time stamp of the library instead and prints a warning the first time it does so. This is almost always ok, except when multiple makefiles update a single library file. In these instances it is possible to miss an update if one is not careful.
This man page is way too long.
WARNINGS
Rules supported by make(1) may not work if transitive closure is turned off (-T, .NOINFER).PWD from csh/ksh will cause problems if a cd operation is performed and -e or -E option is used.
Using internal macros such as COMMAND, may wreak havoc if you don't understand their functionality.
Index
- NAME
- SYNOPSIS
- DESCRIPTION
- OPTIONS
- INDEX
- STARTUP
- SYNTAX
- ATTRIBUTES
- MACROS
- RULES AND TARGETS
- RECIPES
- TEXT DIVERSIONS
- SPECIAL TARGETS
- SPECIAL MACROS
- CONTROL MACROS
- RUNTIME MACROS
- FUNCTION MACROS
- CONDITIONAL MACROS
- DYNAMIC PREREQUISITES
- BINDING TARGETS
- PERCENT() RULES AND MAKING INFERENCES
- MAKING TARGETS
- MAKING LIBRARIES
- KEEP STATE
- MULTI PROCESSING
- CONDITIONALS
- EXAMPLES
- COMPATIBILITY
- LIMITS
- PORTABILITY
- FILES
- SEE ALSO
- AUTHOR
- BUGS
- WARNINGS
This document was created by man2html from the dmake manual page.
