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3 .\" Copyright (c) 1990, 1993
4 .\" The Regents of the University of California. All rights reserved.
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9 .\" 1. Redistributions of source code must retain the above copyright
10 .\" notice, this list of conditions and the following disclaimer.
11 .\" 2. Redistributions in binary form must reproduce the above copyright
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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
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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 scope.
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 scope 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.DEPENDFILE
813 Names the makefile (default
815 from which generated dependencies are read.
816 .It Va .MAKE.EXPAND_VARIABLES
817 A boolean that controls the default behavior of the
820 If true, variable values printed with
822 are fully expanded; if false, the raw variable contents (which may
823 include additional unexpanded variable references) are shown.
824 .It Va .MAKE.EXPORTED
825 The list of variables exported by
831 .It Va .MAKE.JOB.PREFIX
836 then output for each target is prefixed with a token
838 the first part of which can be controlled via
839 .Va .MAKE.JOB.PREFIX .
842 is empty, no token is printed.
845 .Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}]
846 would produce tokens like
847 .Ql ---make[1234] target ---
848 making it easier to track the degree of parallelism being achieved.
850 The environment variable
852 may contain anything that
856 Anything specified on
858 command line is appended to the
860 variable which is then
861 entered into the environment for all programs which
865 The recursion depth of
867 The initial instance of
869 will be 0, and an incremented value is put into the environment
870 to be seen by the next generation.
871 This allows tests like:
872 .Li .if ${.MAKE.LEVEL} == 0
873 to protect things which should only be evaluated in the initial instance of
875 .It Va .MAKE.MAKEFILE_PREFERENCE
876 The ordered list of makefile names
883 .It Va .MAKE.MAKEFILES
884 The list of makefiles read by
886 which is useful for tracking dependencies.
887 Each makefile is recorded only once, regardless of the number of times read.
889 Processed after reading all makefiles.
890 Can affect the mode that
893 It can contain a number of keywords:
894 .Bl -hang -width missing-filemon=bf.
904 into "meta" mode, where meta files are created for each target
905 to capture the command run, the output generated and if
907 is available, the system calls which are of interest to
909 The captured output can be very useful when diagnosing errors.
910 .It Pa curdirOk= Ar bf
913 will not create .meta files in
915 This can be overridden by setting
917 to a value which represents True.
918 .It Pa missing-meta= Ar bf
921 is True, then a missing .meta file makes the target out-of-date.
922 .It Pa missing-filemon= Ar bf
925 is True, then missing filemon data makes the target out-of-date.
930 For debugging, it can be useful to include the environment
933 If in "meta" mode, print a clue about the target being built.
934 This is useful if the build is otherwise running silently.
935 The message printed the value of:
936 .Va .MAKE.META.PREFIX .
938 Some makefiles have commands which are simply not stable.
939 This keyword causes them to be ignored for
940 determining whether a target is out of date in "meta" mode.
946 is True, when a .meta file is created, mark the target
949 .It Va .MAKE.META.BAILIWICK
950 In "meta" mode, provides a list of prefixes which
951 match the directories controlled by
953 If a file that was generated outside of
955 but within said bailiwick is missing,
956 the current target is considered out-of-date.
957 .It Va .MAKE.META.CREATED
958 In "meta" mode, this variable contains a list of all the meta files
960 If not empty, it can be used to trigger processing of
961 .Va .MAKE.META.FILES .
962 .It Va .MAKE.META.FILES
963 In "meta" mode, this variable contains a list of all the meta files
964 used (updated or not).
965 This list can be used to process the meta files to extract dependency
967 .It Va .MAKE.META.IGNORE_PATHS
968 Provides a list of path prefixes that should be ignored;
969 because the contents are expected to change over time.
970 The default list includes:
971 .Ql Pa /dev /etc /proc /tmp /var/run /var/tmp
972 .It Va .MAKE.META.IGNORE_PATTERNS
973 Provides a list of patterns to match against pathnames.
974 Ignore any that match.
975 .It Va .MAKE.META.IGNORE_FILTER
976 Provides a list of variable modifiers to apply to each pathname.
977 Ignore if the expansion is an empty string.
978 .It Va .MAKE.META.PREFIX
979 Defines the message printed for each meta file updated in "meta verbose" mode.
980 The default value is:
981 .Dl Building ${.TARGET:H:tA}/${.TARGET:T}
982 .It Va .MAKEOVERRIDES
983 This variable is used to record the names of variables assigned to
984 on the command line, so that they may be exported as part of
986 This behavior can be disabled by assigning an empty value to
987 .Ql Va .MAKEOVERRIDES
989 Extra variables can be exported from a makefile
990 by appending their names to
991 .Ql Va .MAKEOVERRIDES .
993 is re-exported whenever
994 .Ql Va .MAKEOVERRIDES
996 .It Va .MAKE.PATH_FILEMON
1001 support, this is set to the path of the device node.
1002 This allows makefiles to test for this support.
1007 The parent process-id of
1009 .It Va .MAKE.SAVE_DOLLARS
1010 value should be a boolean that controls whether
1012 are preserved when doing
1015 The default is false, for backwards compatibility.
1016 Set to true for compatability with other makes.
1021 per normal evaluation rules.
1026 The group-id running
1028 .It Va MAKE_PRINT_VAR_ON_ERROR
1031 stops due to an error, it sets
1032 .Ql Va .ERROR_TARGET
1033 to the name of the target that failed,
1035 to the commands of the failed target,
1036 and in "meta" mode, it also sets
1041 .Ql Va .ERROR_META_FILE
1042 to the path of the meta file (if any) describing the failed target.
1043 It then prints its name and the value of
1045 as well as the value of any variables named in
1046 .Ql Va MAKE_PRINT_VAR_ON_ERROR .
1048 This variable is simply assigned a newline character as its value.
1049 This allows expansions using the
1051 modifier to put a newline between
1052 iterations of the loop rather than a space.
1053 For example, the printing of
1054 .Ql Va MAKE_PRINT_VAR_ON_ERROR
1055 could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}.
1057 A path to the directory where the targets are built.
1058 Its value is determined by trying to
1060 to the following directories in order and using the first match:
1063 .Ev ${MAKEOBJDIRPREFIX}${.CURDIR}
1066 .Ql Ev MAKEOBJDIRPREFIX
1067 is set in the environment or on the command line.)
1073 is set in the environment or on the command line.)
1075 .Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE}
1077 .Ev ${.CURDIR} Ns Pa /obj
1079 .Pa /usr/obj/ Ns Ev ${.CURDIR}
1084 Variable expansion is performed on the value before it's used,
1085 so expressions such as
1086 .Dl ${.CURDIR:S,^/usr/src,/var/obj,}
1088 This is especially useful with
1092 may be modified in the makefile via the special target
1098 to the specified directory if it exists, and set
1102 to that directory before executing any targets.
1104 Except in the case of an explicit
1108 will check that the specified directory is writable and ignore it if not.
1109 This check can be skipped by setting the environment variable
1110 .Ql Ev MAKE_OBJDIR_CHECK_WRITABLE
1114 A path to the directory of the current
1118 The basename of the current
1123 are both set only while the
1126 If you want to retain their current values, assign them to a variable
1127 using assignment with expansion:
1130 A variable that represents the list of directories that
1132 will search for files.
1133 The search list should be updated using the target
1135 rather than the variable.
1137 Alternate path to the current directory.
1141 to the canonical path given by
1143 However, if the environment variable
1145 is set and gives a path to the current directory, then
1152 This behavior is disabled if
1153 .Ql Ev MAKEOBJDIRPREFIX
1156 contains a variable transform.
1158 is set to the value of
1160 for all programs which
1164 The pathname of the shell used to run target scripts.
1167 The list of targets explicitly specified on the command line, if any.
1171 lists of directories that
1173 will search for files.
1174 The variable is supported for compatibility with old make programs only,
1179 .Ss Variable modifiers
1180 Variable expansion may be modified to select or modify each word of the
1183 is white-space delimited sequence of characters).
1184 The general format of a variable expansion is as follows:
1186 .Dl ${variable[:modifier[:...]]}
1188 Each modifier begins with a colon,
1189 which may be escaped with a backslash
1192 A set of modifiers can be specified via a variable, as follows:
1194 .Dl modifier_variable=modifier[:...]
1195 .Dl ${variable:${modifier_variable}[:...]}
1197 In this case the first modifier in the modifier_variable does not
1198 start with a colon, since that must appear in the referencing
1200 If any of the modifiers in the modifier_variable contain a dollar sign
1202 these must be doubled to avoid early expansion.
1204 The supported modifiers are:
1207 Replaces each word in the variable with its suffix.
1209 Replaces each word in the variable with everything but the last component.
1210 .It Cm \&:M Ns Ar pattern
1211 Selects only those words that match
1213 The standard shell wildcard characters
1220 The wildcard characters may be escaped with a backslash
1222 As a consequence of the way values are split into words, matched,
1223 and then joined, a construct like
1225 will normalize the inter-word spacing, removing all leading and
1226 trailing space, and converting multiple consecutive spaces
1229 .It Cm \&:N Ns Ar pattern
1230 This is identical to
1232 but selects all words which do not match
1235 Orders every word in variable alphabetically.
1237 Orders every word in variable in reverse alphabetical order.
1239 Shuffles the words in variable.
1240 The results will be different each time you are referring to the
1241 modified variable; use the assignment with expansion
1243 to prevent such behavior.
1245 .Bd -literal -offset indent
1246 LIST= uno due tre quattro
1247 RANDOM_LIST= ${LIST:Ox}
1248 STATIC_RANDOM_LIST:= ${LIST:Ox}
1251 @echo "${RANDOM_LIST}"
1252 @echo "${RANDOM_LIST}"
1253 @echo "${STATIC_RANDOM_LIST}"
1254 @echo "${STATIC_RANDOM_LIST}"
1256 may produce output similar to:
1257 .Bd -literal -offset indent
1264 Quotes every shell meta-character in the variable, so that it can be passed
1265 safely to the shell.
1267 Quotes every shell meta-character in the variable, and also doubles
1269 characters so that it can be passed
1270 safely through recursive invocations of
1272 This is equivalent to:
1273 .Sq \&:S/\e\&$/&&/g:Q .
1275 Replaces each word in the variable with everything but its suffix.
1276 .It Cm \&:range[=count]
1277 The value is an integer sequence representing the words of the original
1278 value, or the supplied
1280 .It Cm \&:gmtime[=utc]
1281 The value is a format string for
1287 value is not provided or is 0, the current time is used.
1289 Computes a 32-bit hash of the value and encode it as hex digits.
1290 .It Cm \&:localtime[=utc]
1291 The value is a format string for
1297 value is not provided or is 0, the current time is used.
1299 Attempts to convert variable to an absolute path using
1301 if that fails, the value is unchanged.
1303 Converts variable to lower-case letters.
1304 .It Cm \&:ts Ns Ar c
1305 Words in the variable are normally separated by a space on expansion.
1306 This modifier sets the separator to the character
1310 is omitted, then no separator is used.
1311 The common escapes (including octal numeric codes) work as expected.
1313 Converts variable to upper-case letters.
1315 Causes the value to be treated as a single word
1316 (possibly containing embedded white space).
1320 Causes the value to be treated as a sequence of
1321 words delimited by white space.
1325 .It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW
1327 Modifies the first occurrence of
1329 in each word of the variable's value, replacing it with
1333 is appended to the last delimiter of the pattern, all occurrences
1334 in each word are replaced.
1337 is appended to the last delimiter of the pattern, only the first occurrence
1341 is appended to the last delimiter of the pattern,
1342 then the value is treated as a single word
1343 (possibly containing embedded white space).
1349 is anchored at the beginning of each word.
1352 ends with a dollar sign
1354 it is anchored at the end of each word.
1365 Any character may be used as a delimiter for the parts of the modifier
1367 The anchoring, ampersand and delimiter characters may be escaped with a
1371 Variable expansion occurs in the normal fashion inside both
1375 with the single exception that a backslash is used to prevent the expansion
1378 not a preceding dollar sign as is usual.
1380 .It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW
1384 modifier is just like the
1386 modifier except that the old and new strings, instead of being
1387 simple strings, are an extended regular expression (see
1395 Normally, the first occurrence of the pattern
1397 in each word of the value is substituted with
1401 modifier causes the substitution to apply to at most one word; the
1403 modifier causes the substitution to apply to as many instances of the
1406 as occur in the word or words it is found in; the
1408 modifier causes the value to be treated as a single word
1409 (possibly containing embedded white space).
1417 are subjected to variable expansion before being parsed as
1418 regular expressions.
1420 Replaces each word in the variable with its last path component.
1422 Removes adjacent duplicate words (like
1425 .It Cm \&:\&? Ar true_string Cm \&: Ar false_string
1427 If the variable name (not its value), when parsed as a .if conditional
1428 expression, evaluates to true, return as its value the
1430 otherwise return the
1432 Since the variable name is used as the expression, \&:\&? must be the
1433 first modifier after the variable name itself - which will, of course,
1434 usually contain variable expansions.
1435 A common error is trying to use expressions like
1436 .Dl ${NUMBERS:M42:?match:no}
1437 which actually tests defined(NUMBERS),
1438 to determine if any words match "42" you need to use something like:
1439 .Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} .
1440 .It Ar :old_string=new_string
1443 style variable substitution.
1444 It must be the last modifier specified.
1449 do not contain the pattern matching character
1451 then it is assumed that they are
1452 anchored at the end of each word, so only suffixes or entire
1453 words may be replaced.
1462 contains the pattern matching character
1466 matches, then the result is the
1470 contains the pattern matching character
1472 then it is not treated specially and it is printed as a literal
1475 If there is more than one pattern matching character
1481 only the first instance is treated specially (as the pattern character);
1482 all subsequent instances are treated as regular characters.
1484 Variable expansion occurs in the normal fashion inside both
1488 with the single exception that a backslash is used to prevent the
1489 expansion of a dollar sign
1491 not a preceding dollar sign as is usual.
1493 .It Cm \&:@ Ar temp Cm @ Ar string Cm @
1495 This is the loop expansion mechanism from the OSF Development
1496 Environment (ODE) make.
1499 loops, expansion occurs at the time of reference.
1502 to each word in the variable and evaluates
1504 The ODE convention is that
1506 should start and end with a period.
1508 .Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
1510 However a single character variable is often more readable:
1511 .Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
1513 Saves the current variable value in
1517 for later reference.
1519 .Bd -literal -offset indent
1520 M_cmpv.units = 1 1000 1000000
1521 M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \&\\
1522 \\* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh
1524 .Dv .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}}
1529 is used to save the result of the
1531 modifier which is later referenced using the index values from
1533 .It Cm \&:U Ns Ar newval
1534 If the variable is undefined,
1537 If the variable is defined, the existing value is returned.
1538 This is another ODE make feature.
1539 It is handy for setting per-target CFLAGS for instance:
1540 .Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
1541 If a value is only required if the variable is undefined, use:
1542 .Dl ${VAR:D:Unewval}
1543 .It Cm \&:D Ns Ar newval
1544 If the variable is defined,
1548 The name of the variable is the value.
1550 The path of the node which has the same name as the variable
1552 If no such node exists or its path is null, then the
1553 name of the variable is used.
1554 In order for this modifier to work, the name (node) must at least have
1555 appeared on the rhs of a dependency.
1557 .It Cm \&:\&! Ar cmd Cm \&!
1559 The output of running
1563 If the variable is non-empty it is run as a command and the output
1564 becomes the new value.
1565 .It Cm \&::= Ns Ar str
1566 The variable is assigned the value
1569 This modifier and its variations are useful in
1570 obscure situations such as wanting to set a variable when shell commands
1572 These assignment modifiers always expand to
1573 nothing, so if appearing in a rule line by themselves should be
1574 preceded with something to keep
1580 helps avoid false matches with the
1584 modifier and since substitution always occurs the
1586 form is vaguely appropriate.
1587 .It Cm \&::?= Ns Ar str
1590 but only if the variable does not already have a value.
1591 .It Cm \&::+= Ns Ar str
1595 .It Cm \&::!= Ns Ar cmd
1596 Assign the output of
1599 .It Cm \&:\&[ Ns Ar range Ns Cm \&]
1600 Selects one or more words from the value,
1601 or performs other operations related to the way in which the
1602 value is divided into words.
1604 Ordinarily, a value is treated as a sequence of words
1605 delimited by white space.
1606 Some modifiers suppress this behavior,
1607 causing a value to be treated as a single word
1608 (possibly containing embedded white space).
1609 An empty value, or a value that consists entirely of white-space,
1610 is treated as a single word.
1611 For the purposes of the
1613 modifier, the words are indexed both forwards using positive integers
1614 (where index 1 represents the first word),
1615 and backwards using negative integers
1616 (where index \-1 represents the last word).
1620 is subjected to variable expansion, and the expanded result is
1621 then interpreted as follows:
1622 .Bl -tag -width index
1625 Selects a single word from the value.
1627 .It Ar start Ns Cm \&.. Ns Ar end
1628 Selects all words from
1635 selects all words from the second word to the last word.
1640 then the words are output in reverse order.
1643 selects all the words from last to first.
1644 If the list is already ordered, then this effectively reverses
1645 the list, but it is more efficient to use
1648 .Ql Cm \&:O:[-1..1] .
1651 Causes subsequent modifiers to treat the value as a single word
1652 (possibly containing embedded white space).
1653 Analogous to the effect of
1662 Causes subsequent modifiers to treat the value as a sequence of words
1663 delimited by white space.
1664 Analogous to the effect of
1669 Returns the number of words in the value.
1672 .Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
1673 Makefile inclusion, conditional structures and for loops reminiscent
1674 of the C programming language are provided in
1676 All such structures are identified by a line beginning with a single
1680 Files are included with either
1681 .Cm \&.include \&< Ns Ar file Ns Cm \&>
1683 .Cm \&.include \&\*q Ns Ar file Ns Cm \&\*q .
1684 Variables between the angle brackets or double quotes are expanded
1685 to form the file name.
1686 If angle brackets are used, the included makefile is expected to be in
1687 the system makefile directory.
1688 If double quotes are used, the including makefile's directory and any
1689 directories specified using the
1691 option are searched before the system
1693 For compatibility with other versions of
1695 .Ql include file ...
1698 If the include statement is written as
1702 then errors locating and/or opening include files are ignored.
1704 If the include statement is written as
1706 not only are errors locating and/or opening include files ignored,
1707 but stale dependencies within the included file will be ignored
1709 .Va .MAKE.DEPENDFILE .
1711 Conditional expressions are also preceded by a single dot as the first
1712 character of a line.
1713 The possible conditionals are as follows:
1715 .It Ic .error Ar message
1716 The message is printed along with the name of the makefile and line number,
1719 will exit immediately.
1720 .It Ic .export Ar variable ...
1721 Export the specified global variable.
1722 If no variable list is provided, all globals are exported
1723 except for internal variables (those that start with
1725 This is not affected by the
1727 flag, so should be used with caution.
1728 For compatibility with other
1731 .Ql export variable=value
1734 Appending a variable name to
1736 is equivalent to exporting a variable.
1737 .It Ic .export-env Ar variable ...
1740 except that the variable is not appended to
1741 .Va .MAKE.EXPORTED .
1742 This allows exporting a value to the environment which is different from that
1746 .It Ic .export-literal Ar variable ...
1749 except that variables in the value are not expanded.
1750 .It Ic .info Ar message
1751 The message is printed along with the name of the makefile and line number.
1752 .It Ic .undef Ar variable ...
1753 Un-define the specified global variables.
1754 Only global variables can be un-defined.
1755 .It Ic .unexport Ar variable ...
1758 The specified global
1760 will be removed from
1761 .Va .MAKE.EXPORTED .
1762 If no variable list is provided, all globals are unexported,
1766 .It Ic .unexport-env
1767 Unexport all globals previously exported and
1768 clear the environment inherited from the parent.
1769 This operation will cause a memory leak of the original environment,
1770 so should be used sparingly.
1773 being 0, would make sense.
1774 Also note that any variables which originated in the parent environment
1775 should be explicitly preserved if desired.
1777 .Bd -literal -offset indent
1778 .Li .if ${.MAKE.LEVEL} == 0
1785 Would result in an environment containing only
1787 which is the minimal useful environment.
1790 will also be pushed into the new environment.
1791 .It Ic .warning Ar message
1792 The message prefixed by
1794 is printed along with the name of the makefile and line number.
1795 .It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ...
1796 Test the value of an expression.
1797 .It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1798 Test the value of a variable.
1799 .It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1800 Test the value of a variable.
1801 .It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1802 Test the target being built.
1803 .It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ...
1804 Test the target being built.
1806 Reverse the sense of the last conditional.
1807 .It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ...
1812 .It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1817 .It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1822 .It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1827 .It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1833 End the body of the conditional.
1838 may be any one of the following:
1839 .Bl -tag -width "Cm XX"
1845 of higher precedence than
1851 will only evaluate a conditional as far as is necessary to determine
1853 Parentheses may be used to change the order of evaluation.
1854 The boolean operator
1856 may be used to logically negate an entire
1858 It is of higher precedence than
1863 may be any of the following:
1864 .Bl -tag -width defined
1866 Takes a variable name as an argument and evaluates to true if the variable
1869 Takes a target name as an argument and evaluates to true if the target
1870 was specified as part of
1872 command line or was declared the default target (either implicitly or
1875 before the line containing the conditional.
1877 Takes a variable, with possible modifiers, and evaluates to true if
1878 the expansion of the variable would result in an empty string.
1880 Takes a file name as an argument and evaluates to true if the file exists.
1881 The file is searched for on the system search path (see
1884 Takes a target name as an argument and evaluates to true if the target
1887 Takes a target name as an argument and evaluates to true if the target
1888 has been defined and has commands associated with it.
1892 may also be an arithmetic or string comparison.
1893 Variable expansion is
1894 performed on both sides of the comparison, after which the numerical
1895 values are compared.
1896 A value is interpreted as hexadecimal if it is
1897 preceded by 0x, otherwise it is decimal; octal numbers are not supported.
1898 The standard C relational operators are all supported.
1900 variable expansion, either the left or right hand side of a
1904 operator is not a numerical value, then
1905 string comparison is performed between the expanded
1907 If no relational operator is given, it is assumed that the expanded
1908 variable is being compared against 0, or an empty string in the case
1909 of a string comparison.
1913 is evaluating one of these conditional expressions, and it encounters
1914 a (white-space separated) word it doesn't recognize, either the
1918 expression is applied to it, depending on the form of the conditional.
1926 expression is applied.
1927 Similarly, if the form is
1933 expression is applied.
1935 If the conditional evaluates to true the parsing of the makefile continues
1937 If it evaluates to false, the following lines are skipped.
1938 In both cases this continues until a
1944 For loops are typically used to apply a set of rules to a list of files.
1945 The syntax of a for loop is:
1947 .Bl -tag -compact -width Ds
1948 .It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression
1955 is evaluated, it is split into words.
1956 On each iteration of the loop, one word is taken and assigned to each
1960 are substituted into the
1962 inside the body of the for loop.
1963 The number of words must come out even; that is, if there are three
1964 iteration variables, the number of words provided must be a multiple
1967 Comments begin with a hash
1969 character, anywhere but in a shell
1970 command line, and continue to the end of an unescaped new line.
1971 .Sh SPECIAL SOURCES (ATTRIBUTES)
1972 .Bl -tag -width .IGNOREx
1974 Target is never out of date, but always execute commands anyway.
1976 Ignore any errors from the commands associated with this target, exactly
1977 as if they all were preceded by a dash
1979 .\" .It Ic .INVISIBLE
1984 Mark all sources of this target as being up-to-date.
1986 Execute the commands associated with this target even if the
1990 options were specified.
1991 Normally used to mark recursive
1994 Create a meta file for the target, even if it is flagged as
1999 Usage in conjunction with
2001 is the most likely case.
2002 In "meta" mode, the target is out-of-date if the meta file is missing.
2004 Do not create a meta file for the target.
2005 Meta files are also not created for
2012 Ignore differences in commands when deciding if target is out of date.
2013 This is useful if the command contains a value which always changes.
2014 If the number of commands change, though, the target will still be out of date.
2015 The same effect applies to any command line that uses the variable
2017 which can be used for that purpose even when not otherwise needed or desired:
2018 .Bd -literal -offset indent
2020 skip-compare-for-some:
2021 @echo this will be compared
2022 @echo this will not ${.OODATE:M.NOMETA_CMP}
2023 @echo this will also be compared
2028 pattern suppresses any expansion of the unwanted variable.
2030 Do not search for the target in the directories specified by
2035 selects the first target it encounters as the default target to be built
2036 if no target was specified.
2037 This source prevents this target from being selected.
2039 If a target is marked with this attribute and
2041 can't figure out how to create it, it will ignore this fact and assume
2042 the file isn't needed or already exists.
2045 correspond to an actual file; it is always considered to be out of date,
2046 and will not be created with the
2049 Suffix-transformation rules are not applied to
2055 is interrupted, it normally removes any partially made targets.
2056 This source prevents the target from being removed.
2061 Do not echo any of the commands associated with this target, exactly
2062 as if they all were preceded by an at sign
2065 Turn the target into
2068 When the target is used as a source for another target, the other target
2069 acquires the commands, sources, and attributes (except for
2073 If the target already has commands, the
2075 target's commands are appended
2082 target commands to the target.
2086 appears in a dependency line, the sources that precede it are
2087 made before the sources that succeed it in the line.
2088 Since the dependents of files are not made until the file itself
2089 could be made, this also stops the dependents being built unless they
2090 are needed for another branch of the dependency tree.
2103 the output is always
2109 The ordering imposed by
2111 is only relevant for parallel makes.
2114 Special targets may not be included with other targets, i.e. they must be
2115 the only target specified.
2116 .Bl -tag -width .BEGINx
2118 Any command lines attached to this target are executed before anything
2123 rule for any target (that was used only as a
2126 can't figure out any other way to create.
2127 Only the shell script is used.
2130 variable of a target that inherits
2133 to the target's own name.
2134 .It Ic .DELETE_ON_ERROR
2135 If this target is present in the makefile, it globally causes make to
2136 delete targets whose commands fail.
2137 (By default, only targets whose commands are interrupted during
2138 execution are deleted.
2139 This is the historical behavior.)
2140 This setting can be used to help prevent half-finished or malformed
2141 targets from being left around and corrupting future rebuilds.
2143 Any command lines attached to this target are executed after everything
2146 Any command lines attached to this target are executed when another target fails.
2149 variable is set to the target that failed.
2151 .Ic MAKE_PRINT_VAR_ON_ERROR .
2153 Mark each of the sources with the
2156 If no sources are specified, this is the equivalent of specifying the
2162 is interrupted, the commands for this target will be executed.
2164 If no target is specified when
2166 is invoked, this target will be built.
2168 This target provides a way to specify flags for
2170 when the makefile is used.
2171 The flags are as if typed to the shell, though the
2175 .\" XXX: NOT YET!!!!
2176 .\" .It Ic .NOTPARALLEL
2177 .\" The named targets are executed in non parallel mode.
2178 .\" If no targets are
2179 .\" specified, then all targets are executed in non parallel mode.
2183 attribute to any specified sources.
2185 Disable parallel mode.
2189 for compatibility with other pmake variants.
2191 The source is a new value for
2197 to it and update the value of
2200 The named targets are made in sequence.
2201 This ordering does not add targets to the list of targets to be made.
2202 Since the dependents of a target do not get built until the target itself
2203 could be built, unless
2205 is built by another part of the dependency graph,
2206 the following is a dependency loop:
2212 The ordering imposed by
2214 is only relevant for parallel makes.
2215 .\" XXX: NOT YET!!!!
2216 .\" .It Ic .PARALLEL
2217 .\" The named targets are executed in parallel mode.
2218 .\" If no targets are
2219 .\" specified, then all targets are executed in parallel mode.
2221 The sources are directories which are to be searched for files not
2222 found in the current directory.
2223 If no sources are specified, any previously specified directories are
2225 If the source is the special
2227 target, then the current working
2228 directory is searched last.
2229 .It Ic .PATH. Ns Va suffix
2232 but applies only to files with a particular suffix.
2233 The suffix must have been previously declared with
2238 attribute to any specified sources.
2242 attribute to any specified sources.
2243 If no sources are specified, the
2245 attribute is applied to every
2250 will use to execute commands.
2251 The sources are a set of
2254 .Bl -tag -width hasErrCtls
2256 This is the minimal specification, used to select one of the built-in
2263 Specifies the path to the shell.
2265 Indicates whether the shell supports exit on error.
2267 The command to turn on error checking.
2269 The command to disable error checking.
2271 The command to turn on echoing of commands executed.
2273 The command to turn off echoing of commands executed.
2275 The output to filter after issuing the
2278 It is typically identical to
2281 The flag to pass the shell to enable error checking.
2283 The flag to pass the shell to enable command echoing.
2285 The string literal to pass the shell that results in a single newline
2286 character when used outside of any quoting characters.
2290 \&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e
2291 check="set \-e" ignore="set +e" \e
2292 echo="set \-v" quiet="set +v" filter="set +v" \e
2293 echoFlag=v errFlag=e newline="'\en'"
2298 attribute to any specified sources.
2299 If no sources are specified, the
2301 attribute is applied to every
2302 command in the file.
2304 This target gets run when a dependency file contains stale entries, having
2306 set to the name of that dependency file.
2308 Each source specifies a suffix to
2310 If no sources are specified, any previously specified suffixes are deleted.
2311 It allows the creation of suffix-transformation rules.
2317 cc \-o ${.TARGET} \-c ${.IMPSRC}
2322 uses the following environment variables, if they exist:
2328 .Ev MAKEOBJDIRPREFIX ,
2334 .Ev MAKEOBJDIRPREFIX
2337 may only be set in the environment or on the command line to
2339 and not as makefile variables;
2340 see the description of
2344 .Bl -tag -width /usr/share/mk -compact
2346 list of dependencies
2348 list of dependencies
2350 list of dependencies
2354 system makefile directory
2357 The basic make syntax is compatible between different versions of make;
2358 however the special variables, variable modifiers and conditionals are not.
2360 An incomplete list of changes in older versions of
2363 The way that .for loop variables are substituted changed after
2365 so that they still appear to be variable expansions.
2366 In particular this stops them being treated as syntax, and removes some
2367 obscure problems using them in .if statements.
2369 The way that parallel makes are scheduled changed in
2371 so that .ORDER and .WAIT apply recursively to the dependent nodes.
2372 The algorithms used may change again in the future.
2373 .Ss Other make dialects
2374 Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not
2375 support most of the features of
2377 as described in this manual.
2379 .Bl -bullet -offset indent
2385 declarations and most functionality pertaining to parallelization.
2386 (GNU make supports parallelization but lacks these features needed to
2387 control it effectively.)
2389 Directives, including for loops and conditionals and most of the
2390 forms of include files.
2391 (GNU make has its own incompatible and less powerful syntax for
2394 All built-in variables that begin with a dot.
2396 Most of the special sources and targets that begin with a dot,
2397 with the notable exception of
2403 Variable modifiers, except for the
2405 string substitution, which does not portably support globbing with
2407 and historically only works on declared suffixes.
2411 variable even in its short form; most makes support this functionality
2412 but its name varies.
2415 Some features are somewhat more portable, such as assignment with
2422 functionality is based on an older feature
2424 found in GNU make and many versions of SVR4 make; however,
2425 historically its behavior is too ill-defined (and too buggy) to rely
2432 variables are more or less universally portable, as is the
2435 Basic use of suffix rules (for files only in the current directory,
2436 not trying to chain transformations together, etc.) is also reasonably
2442 is derived from NetBSD
2444 It uses autoconf to facilitate portability to other platforms.
2452 implementation is based on Adam De Boor's pmake program which was written
2453 for Sprite at Berkeley.
2454 It was designed to be a parallel distributed make running jobs on different
2455 machines using a daemon called
2458 Historically the target/dependency
2460 has been used to FoRCe rebuilding (since the target/dependency
2461 does not exist... unless someone creates an
2467 syntax is difficult to parse without actually acting on the data.
2468 For instance, finding the end of a variable's use should involve scanning
2469 each of the modifiers, using the correct terminator for each field.
2472 just counts {} and () in order to find the end of a variable expansion.
2474 There is no way of escaping a space character in a filename.