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3 .\" Copyright (c) 1990, 1993
4 .\" The Regents of the University of California. All rights reserved.
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7 .\" modification, are permitted provided that the following conditions
9 .\" 1. Redistributions of source code must retain the above copyright
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11 .\" 2. Redistributions in binary form must reproduce the above copyright
12 .\" notice, this list of conditions and the following disclaimer in the
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16 .\" without specific prior written permission.
18 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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30 .\" from: @(#)make.1 8.4 (Berkeley) 3/19/94
37 .Nd maintain program dependencies
56 is a program designed to simplify the maintenance of other programs.
57 Its input is a list of specifications as to the files upon which programs
58 and other files depend.
61 makefile option is given,
67 in order to find the specifications.
70 exists, it is read (see
73 This manual page is intended as a reference document only.
74 For a more thorough description of
76 and makefiles, please refer to
77 .%T "PMake \- A Tutorial" .
80 will prepend the contents of the
82 environment variable to the command line arguments before parsing them.
84 The options are as follows:
87 Try to be backwards compatible by executing a single shell per command and
88 by executing the commands to make the sources of a dependency line in sequence.
92 before reading the makefiles or doing anything else.
95 options are specified, each is interpreted relative to the previous one:
96 .Fl C Pa / Fl C Pa etc
102 to be 1, in the global context.
104 Turn on debugging, and specify which portions of
106 are to print debugging information.
107 Unless the flags are preceded by
109 they are added to the
111 environment variable and will be processed by any child make processes.
112 By default, debugging information is printed to standard error,
113 but this can be changed using the
116 The debugging output is always unbuffered; in addition, if debugging
117 is enabled but debugging output is not directed to standard output,
118 then the standard output is line buffered.
120 is one or more of the following:
123 Print all possible debugging information;
124 equivalent to specifying all of the debugging flags.
126 Print debugging information about archive searching and caching.
128 Print debugging information about current working directory.
130 Print debugging information about conditional evaluation.
132 Print debugging information about directory searching and caching.
134 Print debugging information about failed commands and targets.
135 .It Ar F Ns Oo Sy \&+ Oc Ns Ar filename
136 Specify where debugging output is written.
137 This must be the last flag, because it consumes the remainder of
139 If the character immediately after the
143 then the file will be opened in append mode;
144 otherwise the file will be overwritten.
149 then debugging output will be written to the
150 standard output or standard error output file descriptors respectively
153 option has no effect).
154 Otherwise, the output will be written to the named file.
155 If the file name ends
159 is replaced by the pid.
161 Print debugging information about loop evaluation.
163 Print the input graph before making anything.
165 Print the input graph after making everything, or before exiting
168 Print the input graph before exiting on error.
170 Print debugging information about hash table operations.
172 Print debugging information about running multiple shells.
175 This will throw errors for variable assignments that do not parse
176 correctly, at the time of assignment so the file and line number
179 Print commands in Makefiles regardless of whether or not they are prefixed by
181 or other "quiet" flags.
182 Also known as "loud" behavior.
184 Print debugging information about "meta" mode decisions about targets.
186 Print debugging information about making targets, including modification
189 Don't delete the temporary command scripts created when running commands.
190 These temporary scripts are created in the directory
193 environment variable, or in
197 is unset or set to the empty string.
198 The temporary scripts are created by
200 and have names of the form
203 This can create many files in
209 Print debugging information about makefile parsing.
211 Print debugging information about suffix-transformation rules.
213 Print debugging information about target list maintenance.
217 option to print raw values of variables, overriding the default behavior
219 .Va .MAKE.EXPAND_VARIABLES .
221 Print debugging information about variable assignment.
223 Run shell commands with
225 so the actual commands are printed as they are executed.
228 Specify that environment variables override macro assignments within
231 Specify a makefile to read instead of the default
237 standard input is read.
238 Multiple makefiles may be specified, and are read in the order specified.
239 .It Fl I Ar directory
240 Specify a directory in which to search for makefiles and included makefiles.
241 The system makefile directory (or directories, see the
243 option) is automatically included as part of this list.
245 Ignore non-zero exit of shell commands in the makefile.
246 Equivalent to specifying
248 before each command line in the makefile.
252 be specified by the user.
256 option is in use in a recursive build, this option is passed by a make
257 to child makes to allow all the make processes in the build to
258 cooperate to avoid overloading the system.
260 Specify the maximum number of jobs that
262 may have running at any one time.
263 The value is saved in
265 Turns compatibility mode off, unless the
267 flag is also specified.
268 When compatibility mode is off, all commands associated with a
269 target are executed in a single shell invocation as opposed to the
270 traditional one shell invocation per line.
271 This can break traditional scripts which change directories on each
272 command invocation and then expect to start with a fresh environment
274 It is more efficient to correct the scripts rather than turn backwards
277 Continue processing after errors are encountered, but only on those targets
278 that do not depend on the target whose creation caused the error.
279 .It Fl m Ar directory
280 Specify a directory in which to search for sys.mk and makefiles included
282 .Li \&< Ns Ar file Ns Li \&> Ns -style
286 option can be used multiple times to form a search path.
287 This path will override the default system include path: /usr/share/mk.
288 Furthermore the system include path will be appended to the search path used
290 .Li \*q Ns Ar file Ns Li \*q Ns -style
291 include statements (see the
295 If a file or directory name in the
299 environment variable) starts with the string
303 will search for the specified file or directory named in the remaining part
304 of the argument string.
305 The search starts with the current directory of
306 the Makefile and then works upward towards the root of the file system.
307 If the search is successful, then the resulting directory replaces the
312 If used, this feature allows
314 to easily search in the current source tree for customized sys.mk files
319 Display the commands that would have been executed, but do not
320 actually execute them unless the target depends on the .MAKE special
321 source (see below) or the command is prefixed with
324 Display the commands which would have been executed, but do not
325 actually execute any of them; useful for debugging top-level makefiles
326 without descending into subdirectories.
328 Do not execute any commands, but exit 0 if the specified targets are
329 up-to-date and 1, otherwise.
331 Do not use the built-in rules specified in the system makefile.
333 Stop processing if an error is encountered.
334 This is the default behavior and the opposite of
337 Do not echo any commands as they are executed.
338 Equivalent to specifying
340 before each command line in the makefile.
341 .It Fl T Ar tracefile
345 append a trace record to
347 for each job started and completed.
349 Rather than re-building a target as specified in the makefile, create it
350 or update its modification time to make it appear up-to-date.
354 Do not build any targets.
355 Multiple instances of this option may be specified;
356 the variables will be printed one per line,
357 with a blank line for each null or undefined variable.
358 The value printed is extracted from the global context after all
359 makefiles have been read.
360 By default, the raw variable contents (which may
361 include additional unexpanded variable references) are shown.
366 then the value will be recursively expanded to its complete resultant
367 text before printing.
368 The expanded value will also be printed if
369 .Va .MAKE.EXPAND_VARIABLES
373 option has not been used to override it.
374 Note that loop-local and target-local variables, as well as values
375 taken temporarily by global variables during makefile processing, are
376 not accessible via this option.
379 debug mode can be used to see these at the cost of generating
380 substantial extraneous output.
384 but the variable is always expanded to its complete value.
386 Treat any warnings during makefile parsing as errors.
388 Print entering and leaving directory messages, pre and post processing.
390 Don't export variables passed on the command line to the environment
392 Variables passed on the command line are still exported
395 environment variable.
396 This option may be useful on systems which have a small limit on the
397 size of command arguments.
398 .It Ar variable=value
399 Set the value of the variable
403 Normally, all values passed on the command line are also exported to
404 sub-makes in the environment.
407 flag disables this behavior.
408 Variable assignments should follow options for POSIX compatibility
409 but no ordering is enforced.
412 There are seven different types of lines in a makefile: file dependency
413 specifications, shell commands, variable assignments, include statements,
414 conditional directives, for loops, and comments.
416 In general, lines may be continued from one line to the next by ending
417 them with a backslash
419 The trailing newline character and initial whitespace on the following
420 line are compressed into a single space.
421 .Sh FILE DEPENDENCY SPECIFICATIONS
422 Dependency lines consist of one or more targets, an operator, and zero
424 This creates a relationship where the targets
427 and are customarily created from them.
428 A target is considered out-of-date if it does not exist, or if its
429 modification time is less than that of any of its sources.
430 An out-of-date target will be re-created, but not until all sources
431 have been examined and themselves re-created as needed.
432 Three operators may be used:
435 Many dependency lines may name this target but only one may have
436 attached shell commands.
437 All sources named in all dependency lines are considered together,
438 and if needed the attached shell commands are run to create or
439 re-create the target.
442 is interrupted, the target is removed.
444 The same, but the target is always re-created whether or not it is out
447 Any dependency line may have attached shell commands, but each one
448 is handled independently: its sources are considered and the attached
449 shell commands are run if the target is out of date with respect to
450 (only) those sources.
451 Thus, different groups of the attached shell commands may be run
452 depending on the circumstances.
455 for dependency lines with no sources, the attached shell
456 commands are always run.
459 the target will not be removed if
463 All dependency lines mentioning a particular target must use the same
466 Targets and sources may contain the shell wildcard values
477 may only be used as part of the final
478 component of the target or source, and must be used to describe existing
482 need not necessarily be used to describe existing files.
483 Expansion is in directory order, not alphabetically as done in the shell.
485 Each target may have associated with it one or more lines of shell
487 used to create the target.
488 Each of the lines in this script
490 be preceded by a tab.
491 (For historical reasons, spaces are not accepted.)
492 While targets can appear in many dependency lines if desired, by
493 default only one of these rules may be followed by a creation
497 operator is used, however, all rules may include scripts and the
498 scripts are executed in the order found.
500 Each line is treated as a separate shell command, unless the end of
501 line is escaped with a backslash
503 in which case that line and the next are combined.
504 .\" The escaped newline is retained and passed to the shell, which
505 .\" normally ignores it.
506 .\" However, the tab at the beginning of the following line is removed.
507 If the first characters of the command are any combination of
512 the command is treated specially.
515 causes the command not to be echoed before it is executed.
518 causes the command to be executed even when
521 This is similar to the effect of the .MAKE special source,
522 except that the effect can be limited to a single line of a script.
525 in compatibility mode
526 causes any non-zero exit status of the command line to be ignored.
530 is run in jobs mode with
532 the entire script for the target is fed to a
533 single instance of the shell.
534 In compatibility (non-jobs) mode, each command is run in a separate process.
535 If the command contains any shell meta characters
536 .Pq Ql #=|^(){};&<>*?[]:$`\e\en
537 it will be passed to the shell; otherwise
539 will attempt direct execution.
540 If a line starts with
542 and the shell has ErrCtl enabled then failure of the command line
543 will be ignored as in compatibility mode.
546 affects the entire job;
547 the script will stop at the first command line that fails,
548 but the target will not be deemed to have failed.
550 Makefiles should be written so that the mode of
552 operation does not change their behavior.
553 For example, any command which needs to use
557 without potentially changing the directory for subsequent commands
558 should be put in parentheses so it executes in a subshell.
559 To force the use of one shell, escape the line breaks so as to make
560 the whole script one command.
562 .Bd -literal -offset indent
563 avoid-chdir-side-effects:
564 @echo Building $@ in `pwd`
565 @(cd ${.CURDIR} && ${MAKE} $@)
568 ensure-one-shell-regardless-of-mode:
569 @echo Building $@ in `pwd`; \e
570 (cd ${.CURDIR} && ${MAKE} $@); \e
580 before executing any targets, each child process
581 starts with that as its current working directory.
582 .Sh VARIABLE ASSIGNMENTS
583 Variables in make are much like variables in the shell, and, by tradition,
584 consist of all upper-case letters.
585 .Ss Variable assignment modifiers
586 The five operators that can be used to assign values to variables are as
590 Assign the value to the variable.
591 Any previous value is overridden.
593 Append the value to the current value of the variable.
595 Assign the value to the variable if it is not already defined.
597 Assign with expansion, i.e. expand the value before assigning it
599 Normally, expansion is not done until the variable is referenced.
601 References to undefined variables are
604 This can cause problems when variable modifiers are used.
606 Expand the value and pass it to the shell for execution and assign
607 the result to the variable.
608 Any newlines in the result are replaced with spaces.
611 Any white-space before the assigned
613 is removed; if the value is being appended, a single space is inserted
614 between the previous contents of the variable and the appended value.
616 Variables are expanded by surrounding the variable name with either
621 and preceding it with
624 If the variable name contains only a single letter, the surrounding
625 braces or parentheses are not required.
626 This shorter form is not recommended.
628 If the variable name contains a dollar, then the name itself is expanded first.
629 This allows almost arbitrary variable names, however names containing dollar,
630 braces, parentheses, or whitespace are really best avoided!
632 If the result of expanding a variable contains a dollar sign
634 the string is expanded again.
636 Variable substitution occurs at three distinct times, depending on where
637 the variable is being used.
640 Variables in dependency lines are expanded as the line is read.
642 Variables in shell commands are expanded when the shell command is
646 loop index variables are expanded on each loop iteration.
647 Note that other variables are not expanded inside loops so
648 the following example code:
649 .Bd -literal -offset indent
663 .Bd -literal -offset indent
668 Because while ${a} contains
670 after the loop is executed, ${b}
675 since after the loop completes ${j} contains
679 The four different classes of variables (in order of increasing precedence)
682 .It Environment variables
683 Variables defined as part of
687 Variables defined in the makefile or in included makefiles.
688 .It Command line variables
689 Variables defined as part of the command line.
691 Variables that are defined specific to a certain target.
694 Local variables are all built in and their values vary magically from
696 It is not currently possible to define new local variables.
697 The seven local variables are as follows:
698 .Bl -tag -width ".ARCHIVE" -offset indent
700 The list of all sources for this target; also known as
703 The name of the archive file; also known as
706 In suffix-transformation rules, the name/path of the source from which the
707 target is to be transformed (the
709 source); also known as
711 It is not defined in explicit rules.
713 The name of the archive member; also known as
716 The list of sources for this target that were deemed out-of-date; also
720 The file prefix of the target, containing only the file portion, no suffix
721 or preceding directory components; also known as
723 The suffix must be one of the known suffixes declared with
725 or it will not be recognized.
727 The name of the target; also known as
729 For compatibility with other makes this is an alias for
731 in archive member rules.
743 are permitted for backward
744 compatibility with historical makefiles and legacy POSIX make and are
747 Variants of these variables with the punctuation followed immediately by
753 are legacy forms equivalent to using the
758 These forms are accepted for compatibility with
760 makefiles and POSIX but are not recommended.
762 Four of the local variables may be used in sources on dependency lines
763 because they expand to the proper value for each target on the line.
770 .Ss Additional built-in variables
773 sets or knows about the following variables:
774 .Bl -tag -width .MAKEOVERRIDES
780 expands to a single dollar
783 The list of all targets encountered in the Makefile.
785 Makefile parsing, lists only those targets encountered thus far.
787 A path to the directory where
790 Refer to the description of
793 .It Va .INCLUDEDFROMDIR
794 The directory of the file this Makefile was included from.
795 .It Va .INCLUDEDFROMFILE
796 The filename of the file this Makefile was included from.
807 The preferred variable to use is the environment variable
809 because it is more compatible with other versions of
811 and cannot be confused with the special target with the same name.
812 .It Va .MAKE.ALWAYS_PASS_JOB_QUEUE
815 whether to pass the descriptors of the job token queue
816 even if the target is not tagged with
820 for backwards compatability with
823 .It Va .MAKE.DEPENDFILE
824 Names the makefile (default
826 from which generated dependencies are read.
827 .It Va .MAKE.EXPAND_VARIABLES
828 A boolean that controls the default behavior of the
831 If true, variable values printed with
833 are fully expanded; if false, the raw variable contents (which may
834 include additional unexpanded variable references) are shown.
835 .It Va .MAKE.EXPORTED
836 The list of variables exported by
842 .It Va .MAKE.JOB.PREFIX
847 then output for each target is prefixed with a token
849 the first part of which can be controlled via
850 .Va .MAKE.JOB.PREFIX .
853 is empty, no token is printed.
856 .Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}]
857 would produce tokens like
858 .Ql ---make[1234] target ---
859 making it easier to track the degree of parallelism being achieved.
861 The environment variable
863 may contain anything that
867 Anything specified on
869 command line is appended to the
871 variable which is then
872 entered into the environment for all programs which
876 The recursion depth of
878 The initial instance of
880 will be 0, and an incremented value is put into the environment
881 to be seen by the next generation.
882 This allows tests like:
883 .Li .if ${.MAKE.LEVEL} == 0
884 to protect things which should only be evaluated in the initial instance of
886 .It Va .MAKE.MAKEFILE_PREFERENCE
887 The ordered list of makefile names
894 .It Va .MAKE.MAKEFILES
895 The list of makefiles read by
897 which is useful for tracking dependencies.
898 Each makefile is recorded only once, regardless of the number of times read.
900 Processed after reading all makefiles.
901 Can affect the mode that
904 It can contain a number of keywords:
905 .Bl -hang -width missing-filemon=bf.
915 into "meta" mode, where meta files are created for each target
916 to capture the command run, the output generated and if
918 is available, the system calls which are of interest to
920 The captured output can be very useful when diagnosing errors.
921 .It Pa curdirOk= Ar bf
924 will not create .meta files in
926 This can be overridden by setting
928 to a value which represents True.
929 .It Pa missing-meta= Ar bf
932 is True, then a missing .meta file makes the target out-of-date.
933 .It Pa missing-filemon= Ar bf
936 is True, then missing filemon data makes the target out-of-date.
941 For debugging, it can be useful to include the environment
944 If in "meta" mode, print a clue about the target being built.
945 This is useful if the build is otherwise running silently.
946 The message printed the value of:
947 .Va .MAKE.META.PREFIX .
949 Some makefiles have commands which are simply not stable.
950 This keyword causes them to be ignored for
951 determining whether a target is out of date in "meta" mode.
957 is True, when a .meta file is created, mark the target
960 .It Va .MAKE.META.BAILIWICK
961 In "meta" mode, provides a list of prefixes which
962 match the directories controlled by
964 If a file that was generated outside of
966 but within said bailiwick is missing,
967 the current target is considered out-of-date.
968 .It Va .MAKE.META.CREATED
969 In "meta" mode, this variable contains a list of all the meta files
971 If not empty, it can be used to trigger processing of
972 .Va .MAKE.META.FILES .
973 .It Va .MAKE.META.FILES
974 In "meta" mode, this variable contains a list of all the meta files
975 used (updated or not).
976 This list can be used to process the meta files to extract dependency
978 .It Va .MAKE.META.IGNORE_PATHS
979 Provides a list of path prefixes that should be ignored;
980 because the contents are expected to change over time.
981 The default list includes:
982 .Ql Pa /dev /etc /proc /tmp /var/run /var/tmp
983 .It Va .MAKE.META.IGNORE_PATTERNS
984 Provides a list of patterns to match against pathnames.
985 Ignore any that match.
986 .It Va .MAKE.META.IGNORE_FILTER
987 Provides a list of variable modifiers to apply to each pathname.
988 Ignore if the expansion is an empty string.
989 .It Va .MAKE.META.PREFIX
990 Defines the message printed for each meta file updated in "meta verbose" mode.
991 The default value is:
992 .Dl Building ${.TARGET:H:tA}/${.TARGET:T}
993 .It Va .MAKEOVERRIDES
994 This variable is used to record the names of variables assigned to
995 on the command line, so that they may be exported as part of
997 This behavior can be disabled by assigning an empty value to
998 .Ql Va .MAKEOVERRIDES
1000 Extra variables can be exported from a makefile
1001 by appending their names to
1002 .Ql Va .MAKEOVERRIDES .
1004 is re-exported whenever
1005 .Ql Va .MAKEOVERRIDES
1007 .It Va .MAKE.PATH_FILEMON
1012 support, this is set to the path of the device node.
1013 This allows makefiles to test for this support.
1018 The parent process-id of
1020 .It Va .MAKE.SAVE_DOLLARS
1021 value should be a boolean that controls whether
1023 are preserved when doing
1026 The default is false, for backwards compatibility.
1027 Set to true for compatability with other makes.
1032 per normal evaluation rules.
1033 .It Va MAKE_PRINT_VAR_ON_ERROR
1036 stops due to an error, it sets
1037 .Ql Va .ERROR_TARGET
1038 to the name of the target that failed,
1040 to the commands of the failed target,
1041 and in "meta" mode, it also sets
1046 .Ql Va .ERROR_META_FILE
1047 to the path of the meta file (if any) describing the failed target.
1048 It then prints its name and the value of
1050 as well as the value of any variables named in
1051 .Ql Va MAKE_PRINT_VAR_ON_ERROR .
1053 This variable is simply assigned a newline character as its value.
1054 This allows expansions using the
1056 modifier to put a newline between
1057 iterations of the loop rather than a space.
1058 For example, the printing of
1059 .Ql Va MAKE_PRINT_VAR_ON_ERROR
1060 could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}.
1062 A path to the directory where the targets are built.
1063 Its value is determined by trying to
1065 to the following directories in order and using the first match:
1068 .Ev ${MAKEOBJDIRPREFIX}${.CURDIR}
1071 .Ql Ev MAKEOBJDIRPREFIX
1072 is set in the environment or on the command line.)
1078 is set in the environment or on the command line.)
1080 .Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE}
1082 .Ev ${.CURDIR} Ns Pa /obj
1084 .Pa /usr/obj/ Ns Ev ${.CURDIR}
1089 Variable expansion is performed on the value before it's used,
1090 so expressions such as
1091 .Dl ${.CURDIR:S,^/usr/src,/var/obj,}
1093 This is especially useful with
1097 may be modified in the makefile via the special target
1103 to the specified directory if it exists, and set
1107 to that directory before executing any targets.
1109 Except in the case of an explicit
1113 will check that the specified directory is writable and ignore it if not.
1114 This check can be skipped by setting the environment variable
1115 .Ql Ev MAKE_OBJDIR_CHECK_WRITABLE
1119 A path to the directory of the current
1123 The basename of the current
1128 are both set only while the
1131 If you want to retain their current values, assign them to a variable
1132 using assignment with expansion:
1135 A variable that represents the list of directories that
1137 will search for files.
1138 The search list should be updated using the target
1140 rather than the variable.
1142 Alternate path to the current directory.
1146 to the canonical path given by
1148 However, if the environment variable
1150 is set and gives a path to the current directory, then
1157 This behavior is disabled if
1158 .Ql Ev MAKEOBJDIRPREFIX
1161 contains a variable transform.
1163 is set to the value of
1165 for all programs which
1169 The pathname of the shell used to run target scripts.
1172 The list of targets explicitly specified on the command line, if any.
1176 lists of directories that
1178 will search for files.
1179 The variable is supported for compatibility with old make programs only,
1184 .Ss Variable modifiers
1185 Variable expansion may be modified to select or modify each word of the
1188 is white-space delimited sequence of characters).
1189 The general format of a variable expansion is as follows:
1191 .Dl ${variable[:modifier[:...]]}
1193 Each modifier begins with a colon,
1194 which may be escaped with a backslash
1197 A set of modifiers can be specified via a variable, as follows:
1199 .Dl modifier_variable=modifier[:...]
1200 .Dl ${variable:${modifier_variable}[:...]}
1202 In this case the first modifier in the modifier_variable does not
1203 start with a colon, since that must appear in the referencing
1205 If any of the modifiers in the modifier_variable contain a dollar sign
1207 these must be doubled to avoid early expansion.
1209 The supported modifiers are:
1212 Replaces each word in the variable with its suffix.
1214 Replaces each word in the variable with everything but the last component.
1215 .It Cm \&:M Ns Ar pattern
1216 Selects only those words that match
1218 The standard shell wildcard characters
1225 The wildcard characters may be escaped with a backslash
1227 As a consequence of the way values are split into words, matched,
1228 and then joined, a construct like
1230 will normalize the inter-word spacing, removing all leading and
1231 trailing space, and converting multiple consecutive spaces
1234 .It Cm \&:N Ns Ar pattern
1235 This is identical to
1237 but selects all words which do not match
1240 Orders every word in variable alphabetically.
1242 Orders every word in variable in reverse alphabetical order.
1244 Shuffles the words in variable.
1245 The results will be different each time you are referring to the
1246 modified variable; use the assignment with expansion
1248 to prevent such behavior.
1250 .Bd -literal -offset indent
1251 LIST= uno due tre quattro
1252 RANDOM_LIST= ${LIST:Ox}
1253 STATIC_RANDOM_LIST:= ${LIST:Ox}
1256 @echo "${RANDOM_LIST}"
1257 @echo "${RANDOM_LIST}"
1258 @echo "${STATIC_RANDOM_LIST}"
1259 @echo "${STATIC_RANDOM_LIST}"
1261 may produce output similar to:
1262 .Bd -literal -offset indent
1269 Quotes every shell meta-character in the variable, so that it can be passed
1270 safely to the shell.
1272 Quotes every shell meta-character in the variable, and also doubles
1274 characters so that it can be passed
1275 safely through recursive invocations of
1277 This is equivalent to:
1278 .Sq \&:S/\e\&$/&&/g:Q .
1280 Replaces each word in the variable with everything but its suffix.
1281 .It Cm \&:range[=count]
1282 The value is an integer sequence representing the words of the original
1283 value, or the supplied
1285 .It Cm \&:gmtime[=utc]
1286 The value is a format string for
1292 value is not provided or is 0, the current time is used.
1294 Computes a 32-bit hash of the value and encode it as hex digits.
1295 .It Cm \&:localtime[=utc]
1296 The value is a format string for
1302 value is not provided or is 0, the current time is used.
1304 Attempts to convert variable to an absolute path using
1306 if that fails, the value is unchanged.
1308 Converts variable to lower-case letters.
1309 .It Cm \&:ts Ns Ar c
1310 Words in the variable are normally separated by a space on expansion.
1311 This modifier sets the separator to the character
1315 is omitted, then no separator is used.
1316 The common escapes (including octal numeric codes) work as expected.
1318 Converts variable to upper-case letters.
1320 Causes the value to be treated as a single word
1321 (possibly containing embedded white space).
1325 Causes the value to be treated as a sequence of
1326 words delimited by white space.
1330 .It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW
1332 Modifies the first occurrence of
1334 in each word of the variable's value, replacing it with
1338 is appended to the last delimiter of the pattern, all occurrences
1339 in each word are replaced.
1342 is appended to the last delimiter of the pattern, only the first occurrence
1346 is appended to the last delimiter of the pattern,
1347 then the value is treated as a single word
1348 (possibly containing embedded white space).
1354 is anchored at the beginning of each word.
1357 ends with a dollar sign
1359 it is anchored at the end of each word.
1370 Any character may be used as a delimiter for the parts of the modifier
1372 The anchoring, ampersand and delimiter characters may be escaped with a
1376 Variable expansion occurs in the normal fashion inside both
1380 with the single exception that a backslash is used to prevent the expansion
1383 not a preceding dollar sign as is usual.
1385 .It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW
1389 modifier is just like the
1391 modifier except that the old and new strings, instead of being
1392 simple strings, are an extended regular expression (see
1400 Normally, the first occurrence of the pattern
1402 in each word of the value is substituted with
1406 modifier causes the substitution to apply to at most one word; the
1408 modifier causes the substitution to apply to as many instances of the
1411 as occur in the word or words it is found in; the
1413 modifier causes the value to be treated as a single word
1414 (possibly containing embedded white space).
1422 are subjected to variable expansion before being parsed as
1423 regular expressions.
1425 Replaces each word in the variable with its last path component.
1427 Removes adjacent duplicate words (like
1430 .It Cm \&:\&? Ar true_string Cm \&: Ar false_string
1432 If the variable name (not its value), when parsed as a .if conditional
1433 expression, evaluates to true, return as its value the
1435 otherwise return the
1437 Since the variable name is used as the expression, \&:\&? must be the
1438 first modifier after the variable name itself - which will, of course,
1439 usually contain variable expansions.
1440 A common error is trying to use expressions like
1441 .Dl ${NUMBERS:M42:?match:no}
1442 which actually tests defined(NUMBERS),
1443 to determine if any words match "42" you need to use something like:
1444 .Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} .
1445 .It Ar :old_string=new_string
1448 style variable substitution.
1449 It must be the last modifier specified.
1454 do not contain the pattern matching character
1456 then it is assumed that they are
1457 anchored at the end of each word, so only suffixes or entire
1458 words may be replaced.
1467 contains the pattern matching character
1471 matches, then the result is the
1475 contains the pattern matching character
1477 then it is not treated specially and it is printed as a literal
1480 If there is more than one pattern matching character
1486 only the first instance is treated specially (as the pattern character);
1487 all subsequent instances are treated as regular characters.
1489 Variable expansion occurs in the normal fashion inside both
1493 with the single exception that a backslash is used to prevent the
1494 expansion of a dollar sign
1496 not a preceding dollar sign as is usual.
1498 .It Cm \&:@ Ar temp Cm @ Ar string Cm @
1500 This is the loop expansion mechanism from the OSF Development
1501 Environment (ODE) make.
1504 loops, expansion occurs at the time of reference.
1507 to each word in the variable and evaluates
1509 The ODE convention is that
1511 should start and end with a period.
1513 .Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
1515 However a single character variable is often more readable:
1516 .Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
1518 Saves the current variable value in
1522 for later reference.
1524 .Bd -literal -offset indent
1525 M_cmpv.units = 1 1000 1000000
1526 M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \&\\
1527 \\* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh
1529 .Dv .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}}
1534 is used to save the result of the
1536 modifier which is later referenced using the index values from
1538 .It Cm \&:U Ns Ar newval
1539 If the variable is undefined,
1542 If the variable is defined, the existing value is returned.
1543 This is another ODE make feature.
1544 It is handy for setting per-target CFLAGS for instance:
1545 .Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
1546 If a value is only required if the variable is undefined, use:
1547 .Dl ${VAR:D:Unewval}
1548 .It Cm \&:D Ns Ar newval
1549 If the variable is defined,
1553 The name of the variable is the value.
1555 The path of the node which has the same name as the variable
1557 If no such node exists or its path is null, then the
1558 name of the variable is used.
1559 In order for this modifier to work, the name (node) must at least have
1560 appeared on the rhs of a dependency.
1562 .It Cm \&:\&! Ar cmd Cm \&!
1564 The output of running
1568 If the variable is non-empty it is run as a command and the output
1569 becomes the new value.
1570 .It Cm \&::= Ns Ar str
1571 The variable is assigned the value
1574 This modifier and its variations are useful in
1575 obscure situations such as wanting to set a variable when shell commands
1577 These assignment modifiers always expand to
1578 nothing, so if appearing in a rule line by themselves should be
1579 preceded with something to keep
1585 helps avoid false matches with the
1589 modifier and since substitution always occurs the
1591 form is vaguely appropriate.
1592 .It Cm \&::?= Ns Ar str
1595 but only if the variable does not already have a value.
1596 .It Cm \&::+= Ns Ar str
1600 .It Cm \&::!= Ns Ar cmd
1601 Assign the output of
1604 .It Cm \&:\&[ Ns Ar range Ns Cm \&]
1605 Selects one or more words from the value,
1606 or performs other operations related to the way in which the
1607 value is divided into words.
1609 Ordinarily, a value is treated as a sequence of words
1610 delimited by white space.
1611 Some modifiers suppress this behavior,
1612 causing a value to be treated as a single word
1613 (possibly containing embedded white space).
1614 An empty value, or a value that consists entirely of white-space,
1615 is treated as a single word.
1616 For the purposes of the
1618 modifier, the words are indexed both forwards using positive integers
1619 (where index 1 represents the first word),
1620 and backwards using negative integers
1621 (where index \-1 represents the last word).
1625 is subjected to variable expansion, and the expanded result is
1626 then interpreted as follows:
1627 .Bl -tag -width index
1630 Selects a single word from the value.
1632 .It Ar start Ns Cm \&.. Ns Ar end
1633 Selects all words from
1640 selects all words from the second word to the last word.
1645 then the words are output in reverse order.
1648 selects all the words from last to first.
1649 If the list is already ordered, then this effectively reverses
1650 the list, but it is more efficient to use
1653 .Ql Cm \&:O:[-1..1] .
1656 Causes subsequent modifiers to treat the value as a single word
1657 (possibly containing embedded white space).
1658 Analogous to the effect of
1667 Causes subsequent modifiers to treat the value as a sequence of words
1668 delimited by white space.
1669 Analogous to the effect of
1674 Returns the number of words in the value.
1677 .Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
1678 Makefile inclusion, conditional structures and for loops reminiscent
1679 of the C programming language are provided in
1681 All such structures are identified by a line beginning with a single
1685 Files are included with either
1686 .Cm \&.include \&< Ns Ar file Ns Cm \&>
1688 .Cm \&.include \&\*q Ns Ar file Ns Cm \&\*q .
1689 Variables between the angle brackets or double quotes are expanded
1690 to form the file name.
1691 If angle brackets are used, the included makefile is expected to be in
1692 the system makefile directory.
1693 If double quotes are used, the including makefile's directory and any
1694 directories specified using the
1696 option are searched before the system
1698 For compatibility with other versions of
1700 .Ql include file ...
1703 If the include statement is written as
1707 then errors locating and/or opening include files are ignored.
1709 If the include statement is written as
1711 not only are errors locating and/or opening include files ignored,
1712 but stale dependencies within the included file will be ignored
1714 .Va .MAKE.DEPENDFILE .
1716 Conditional expressions are also preceded by a single dot as the first
1717 character of a line.
1718 The possible conditionals are as follows:
1720 .It Ic .error Ar message
1721 The message is printed along with the name of the makefile and line number,
1724 will exit immediately.
1725 .It Ic .export Ar variable ...
1726 Export the specified global variable.
1727 If no variable list is provided, all globals are exported
1728 except for internal variables (those that start with
1730 This is not affected by the
1732 flag, so should be used with caution.
1733 For compatibility with other
1736 .Ql export variable=value
1739 Appending a variable name to
1741 is equivalent to exporting a variable.
1742 .It Ic .export-env Ar variable ...
1745 except that the variable is not appended to
1746 .Va .MAKE.EXPORTED .
1747 This allows exporting a value to the environment which is different from that
1751 .It Ic .export-literal Ar variable ...
1754 except that variables in the value are not expanded.
1755 .It Ic .info Ar message
1756 The message is printed along with the name of the makefile and line number.
1757 .It Ic .undef Ar variable
1758 Un-define the specified global variable.
1759 Only global variables may be un-defined.
1760 .It Ic .unexport Ar variable ...
1763 The specified global
1765 will be removed from
1766 .Va .MAKE.EXPORTED .
1767 If no variable list is provided, all globals are unexported,
1771 .It Ic .unexport-env
1772 Unexport all globals previously exported and
1773 clear the environment inherited from the parent.
1774 This operation will cause a memory leak of the original environment,
1775 so should be used sparingly.
1778 being 0, would make sense.
1779 Also note that any variables which originated in the parent environment
1780 should be explicitly preserved if desired.
1782 .Bd -literal -offset indent
1783 .Li .if ${.MAKE.LEVEL} == 0
1790 Would result in an environment containing only
1792 which is the minimal useful environment.
1795 will also be pushed into the new environment.
1796 .It Ic .warning Ar message
1797 The message prefixed by
1799 is printed along with the name of the makefile and line number.
1800 .It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ...
1801 Test the value of an expression.
1802 .It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1803 Test the value of a variable.
1804 .It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1805 Test the value of a variable.
1806 .It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1807 Test the target being built.
1808 .It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ...
1809 Test the target being built.
1811 Reverse the sense of the last conditional.
1812 .It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ...
1817 .It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1822 .It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1827 .It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1832 .It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1838 End the body of the conditional.
1843 may be any one of the following:
1844 .Bl -tag -width "Cm XX"
1850 of higher precedence than
1856 will only evaluate a conditional as far as is necessary to determine
1858 Parentheses may be used to change the order of evaluation.
1859 The boolean operator
1861 may be used to logically negate an entire
1863 It is of higher precedence than
1868 may be any of the following:
1869 .Bl -tag -width defined
1871 Takes a variable name as an argument and evaluates to true if the variable
1874 Takes a target name as an argument and evaluates to true if the target
1875 was specified as part of
1877 command line or was declared the default target (either implicitly or
1880 before the line containing the conditional.
1882 Takes a variable, with possible modifiers, and evaluates to true if
1883 the expansion of the variable would result in an empty string.
1885 Takes a file name as an argument and evaluates to true if the file exists.
1886 The file is searched for on the system search path (see
1889 Takes a target name as an argument and evaluates to true if the target
1892 Takes a target name as an argument and evaluates to true if the target
1893 has been defined and has commands associated with it.
1897 may also be an arithmetic or string comparison.
1898 Variable expansion is
1899 performed on both sides of the comparison, after which the numerical
1900 values are compared.
1901 A value is interpreted as hexadecimal if it is
1902 preceded by 0x, otherwise it is decimal; octal numbers are not supported.
1903 The standard C relational operators are all supported.
1905 variable expansion, either the left or right hand side of a
1909 operator is not a numerical value, then
1910 string comparison is performed between the expanded
1912 If no relational operator is given, it is assumed that the expanded
1913 variable is being compared against 0, or an empty string in the case
1914 of a string comparison.
1918 is evaluating one of these conditional expressions, and it encounters
1919 a (white-space separated) word it doesn't recognize, either the
1923 expression is applied to it, depending on the form of the conditional.
1931 expression is applied.
1932 Similarly, if the form is
1938 expression is applied.
1940 If the conditional evaluates to true the parsing of the makefile continues
1942 If it evaluates to false, the following lines are skipped.
1943 In both cases this continues until a
1949 For loops are typically used to apply a set of rules to a list of files.
1950 The syntax of a for loop is:
1952 .Bl -tag -compact -width Ds
1953 .It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression
1960 is evaluated, it is split into words.
1961 On each iteration of the loop, one word is taken and assigned to each
1965 are substituted into the
1967 inside the body of the for loop.
1968 The number of words must come out even; that is, if there are three
1969 iteration variables, the number of words provided must be a multiple
1972 Comments begin with a hash
1974 character, anywhere but in a shell
1975 command line, and continue to the end of an unescaped new line.
1976 .Sh SPECIAL SOURCES (ATTRIBUTES)
1977 .Bl -tag -width .IGNOREx
1979 Target is never out of date, but always execute commands anyway.
1981 Ignore any errors from the commands associated with this target, exactly
1982 as if they all were preceded by a dash
1984 .\" .It Ic .INVISIBLE
1989 Mark all sources of this target as being up-to-date.
1991 Execute the commands associated with this target even if the
1995 options were specified.
1996 Normally used to mark recursive
1999 Create a meta file for the target, even if it is flagged as
2004 Usage in conjunction with
2006 is the most likely case.
2007 In "meta" mode, the target is out-of-date if the meta file is missing.
2009 Do not create a meta file for the target.
2010 Meta files are also not created for
2017 Ignore differences in commands when deciding if target is out of date.
2018 This is useful if the command contains a value which always changes.
2019 If the number of commands change, though, the target will still be out of date.
2020 The same effect applies to any command line that uses the variable
2022 which can be used for that purpose even when not otherwise needed or desired:
2023 .Bd -literal -offset indent
2025 skip-compare-for-some:
2026 @echo this will be compared
2027 @echo this will not ${.OODATE:M.NOMETA_CMP}
2028 @echo this will also be compared
2033 pattern suppresses any expansion of the unwanted variable.
2035 Do not search for the target in the directories specified by
2040 selects the first target it encounters as the default target to be built
2041 if no target was specified.
2042 This source prevents this target from being selected.
2044 If a target is marked with this attribute and
2046 can't figure out how to create it, it will ignore this fact and assume
2047 the file isn't needed or already exists.
2050 correspond to an actual file; it is always considered to be out of date,
2051 and will not be created with the
2054 Suffix-transformation rules are not applied to
2060 is interrupted, it normally removes any partially made targets.
2061 This source prevents the target from being removed.
2066 Do not echo any of the commands associated with this target, exactly
2067 as if they all were preceded by an at sign
2070 Turn the target into
2073 When the target is used as a source for another target, the other target
2074 acquires the commands, sources, and attributes (except for
2078 If the target already has commands, the
2080 target's commands are appended
2087 target commands to the target.
2091 appears in a dependency line, the sources that precede it are
2092 made before the sources that succeed it in the line.
2093 Since the dependents of files are not made until the file itself
2094 could be made, this also stops the dependents being built unless they
2095 are needed for another branch of the dependency tree.
2108 the output is always
2114 The ordering imposed by
2116 is only relevant for parallel makes.
2119 Special targets may not be included with other targets, i.e. they must be
2120 the only target specified.
2121 .Bl -tag -width .BEGINx
2123 Any command lines attached to this target are executed before anything
2128 rule for any target (that was used only as a
2131 can't figure out any other way to create.
2132 Only the shell script is used.
2135 variable of a target that inherits
2138 to the target's own name.
2139 .It Ic .DELETE_ON_ERROR
2140 If this target is present in the makefile, it globally causes make to
2141 delete targets whose commands fail.
2142 (By default, only targets whose commands are interrupted during
2143 execution are deleted.
2144 This is the historical behavior.)
2145 This setting can be used to help prevent half-finished or malformed
2146 targets from being left around and corrupting future rebuilds.
2148 Any command lines attached to this target are executed after everything
2151 Any command lines attached to this target are executed when another target fails.
2154 variable is set to the target that failed.
2156 .Ic MAKE_PRINT_VAR_ON_ERROR .
2158 Mark each of the sources with the
2161 If no sources are specified, this is the equivalent of specifying the
2167 is interrupted, the commands for this target will be executed.
2169 If no target is specified when
2171 is invoked, this target will be built.
2173 This target provides a way to specify flags for
2175 when the makefile is used.
2176 The flags are as if typed to the shell, though the
2180 .\" XXX: NOT YET!!!!
2181 .\" .It Ic .NOTPARALLEL
2182 .\" The named targets are executed in non parallel mode.
2183 .\" If no targets are
2184 .\" specified, then all targets are executed in non parallel mode.
2188 attribute to any specified sources.
2190 Disable parallel mode.
2194 for compatibility with other pmake variants.
2196 The source is a new value for
2202 to it and update the value of
2205 The named targets are made in sequence.
2206 This ordering does not add targets to the list of targets to be made.
2207 Since the dependents of a target do not get built until the target itself
2208 could be built, unless
2210 is built by another part of the dependency graph,
2211 the following is a dependency loop:
2217 The ordering imposed by
2219 is only relevant for parallel makes.
2220 .\" XXX: NOT YET!!!!
2221 .\" .It Ic .PARALLEL
2222 .\" The named targets are executed in parallel mode.
2223 .\" If no targets are
2224 .\" specified, then all targets are executed in parallel mode.
2226 The sources are directories which are to be searched for files not
2227 found in the current directory.
2228 If no sources are specified, any previously specified directories are
2230 If the source is the special
2232 target, then the current working
2233 directory is searched last.
2234 .It Ic .PATH. Ns Va suffix
2237 but applies only to files with a particular suffix.
2238 The suffix must have been previously declared with
2243 attribute to any specified sources.
2247 attribute to any specified sources.
2248 If no sources are specified, the
2250 attribute is applied to every
2255 will use to execute commands.
2256 The sources are a set of
2259 .Bl -tag -width hasErrCtls
2261 This is the minimal specification, used to select one of the built-in
2268 Specifies the path to the shell.
2270 Indicates whether the shell supports exit on error.
2272 The command to turn on error checking.
2274 The command to disable error checking.
2276 The command to turn on echoing of commands executed.
2278 The command to turn off echoing of commands executed.
2280 The output to filter after issuing the
2283 It is typically identical to
2286 The flag to pass the shell to enable error checking.
2288 The flag to pass the shell to enable command echoing.
2290 The string literal to pass the shell that results in a single newline
2291 character when used outside of any quoting characters.
2295 \&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e
2296 check="set \-e" ignore="set +e" \e
2297 echo="set \-v" quiet="set +v" filter="set +v" \e
2298 echoFlag=v errFlag=e newline="'\en'"
2303 attribute to any specified sources.
2304 If no sources are specified, the
2306 attribute is applied to every
2307 command in the file.
2309 This target gets run when a dependency file contains stale entries, having
2311 set to the name of that dependency file.
2313 Each source specifies a suffix to
2315 If no sources are specified, any previously specified suffixes are deleted.
2316 It allows the creation of suffix-transformation rules.
2322 cc \-o ${.TARGET} \-c ${.IMPSRC}
2327 uses the following environment variables, if they exist:
2333 .Ev MAKEOBJDIRPREFIX ,
2339 .Ev MAKEOBJDIRPREFIX
2342 may only be set in the environment or on the command line to
2344 and not as makefile variables;
2345 see the description of
2349 .Bl -tag -width /usr/share/mk -compact
2351 list of dependencies
2353 list of dependencies
2355 list of dependencies
2359 system makefile directory
2362 The basic make syntax is compatible between different versions of make;
2363 however the special variables, variable modifiers and conditionals are not.
2365 An incomplete list of changes in older versions of
2368 The way that .for loop variables are substituted changed after
2370 so that they still appear to be variable expansions.
2371 In particular this stops them being treated as syntax, and removes some
2372 obscure problems using them in .if statements.
2374 The way that parallel makes are scheduled changed in
2376 so that .ORDER and .WAIT apply recursively to the dependent nodes.
2377 The algorithms used may change again in the future.
2378 .Ss Other make dialects
2379 Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not
2380 support most of the features of
2382 as described in this manual.
2384 .Bl -bullet -offset indent
2390 declarations and most functionality pertaining to parallelization.
2391 (GNU make supports parallelization but lacks these features needed to
2392 control it effectively.)
2394 Directives, including for loops and conditionals and most of the
2395 forms of include files.
2396 (GNU make has its own incompatible and less powerful syntax for
2399 All built-in variables that begin with a dot.
2401 Most of the special sources and targets that begin with a dot,
2402 with the notable exception of
2408 Variable modifiers, except for the
2410 string substitution, which does not portably support globbing with
2412 and historically only works on declared suffixes.
2416 variable even in its short form; most makes support this functionality
2417 but its name varies.
2420 Some features are somewhat more portable, such as assignment with
2427 functionality is based on an older feature
2429 found in GNU make and many versions of SVR4 make; however,
2430 historically its behavior is too ill-defined (and too buggy) to rely
2437 variables are more or less universally portable, as is the
2440 Basic use of suffix rules (for files only in the current directory,
2441 not trying to chain transformations together, etc.) is also reasonably
2445 .Xr style.Makefile 5
2453 implementation is based on Adam De Boor's pmake program which was written
2454 for Sprite at Berkeley.
2455 It was designed to be a parallel distributed make running jobs on different
2456 machines using a daemon called
2459 Historically the target/dependency
2461 has been used to FoRCe rebuilding (since the target/dependency
2462 does not exist... unless someone creates an
2468 syntax is difficult to parse without actually acting on the data.
2469 For instance, finding the end of a variable's use should involve scanning
2470 each of the modifiers, using the correct terminator for each field.
2473 just counts {} and () in order to find the end of a variable expansion.
2475 There is no way of escaping a space character in a filename.