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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
10 .\" notice, this list of conditions and the following disclaimer.
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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15 .\" may be used to endorse or promote products derived from this software
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 Do not echo any commands as they are executed.
334 Equivalent to specifying
336 before each command line in the makefile.
337 .It Fl T Ar tracefile
341 append a trace record to
343 for each job started and completed.
345 Rather than re-building a target as specified in the makefile, create it
346 or update its modification time to make it appear up-to-date.
350 Do not build any targets.
351 Multiple instances of this option may be specified;
352 the variables will be printed one per line,
353 with a blank line for each null or undefined variable.
354 The value printed is extracted from the global context after all
355 makefiles have been read.
356 By default, the raw variable contents (which may
357 include additional unexpanded variable references) are shown.
362 then the value will be recursively expanded to its complete resultant
363 text before printing.
364 The expanded value will also be printed if
365 .Va .MAKE.EXPAND_VARIABLES
369 option has not been used to override it.
370 Note that loop-local and target-local variables, as well as values
371 taken temporarily by global variables during makefile processing, are
372 not accessible via this option.
375 debug mode can be used to see these at the cost of generating
376 substantial extraneous output.
380 but the variable is always expanded to its complete value.
382 Treat any warnings during makefile parsing as errors.
384 Print entering and leaving directory messages, pre and post processing.
386 Don't export variables passed on the command line to the environment
388 Variables passed on the command line are still exported
391 environment variable.
392 This option may be useful on systems which have a small limit on the
393 size of command arguments.
394 .It Ar variable=value
395 Set the value of the variable
399 Normally, all values passed on the command line are also exported to
400 sub-makes in the environment.
403 flag disables this behavior.
404 Variable assignments should follow options for POSIX compatibility
405 but no ordering is enforced.
408 There are seven different types of lines in a makefile: file dependency
409 specifications, shell commands, variable assignments, include statements,
410 conditional directives, for loops, and comments.
412 In general, lines may be continued from one line to the next by ending
413 them with a backslash
415 The trailing newline character and initial whitespace on the following
416 line are compressed into a single space.
417 .Sh FILE DEPENDENCY SPECIFICATIONS
418 Dependency lines consist of one or more targets, an operator, and zero
420 This creates a relationship where the targets
423 and are customarily created from them.
424 A target is considered out-of-date if it does not exist, or if its
425 modification time is less than that of any of its sources.
426 An out-of-date target will be re-created, but not until all sources
427 have been examined and themselves re-created as needed.
428 Three operators may be used:
431 Many dependency lines may name this target but only one may have
432 attached shell commands.
433 All sources named in all dependency lines are considered together,
434 and if needed the attached shell commands are run to create or
435 re-create the target.
438 is interrupted, the target is removed.
440 The same, but the target is always re-created whether or not it is out
443 Any dependency line may have attached shell commands, but each one
444 is handled independently: its sources are considered and the attached
445 shell commands are run if the target is out of date with respect to
446 (only) those sources.
447 Thus, different groups of the attached shell commands may be run
448 depending on the circumstances.
451 for dependency lines with no sources, the attached shell
452 commands are always run.
455 the target will not be removed if
459 All dependency lines mentioning a particular target must use the same
462 Targets and sources may contain the shell wildcard values
473 may only be used as part of the final
474 component of the target or source, and must be used to describe existing
478 need not necessarily be used to describe existing files.
479 Expansion is in directory order, not alphabetically as done in the shell.
481 Each target may have associated with it one or more lines of shell
483 used to create the target.
484 Each of the lines in this script
486 be preceded by a tab.
487 (For historical reasons, spaces are not accepted.)
488 While targets can appear in many dependency lines if desired, by
489 default only one of these rules may be followed by a creation
493 operator is used, however, all rules may include scripts and the
494 scripts are executed in the order found.
496 Each line is treated as a separate shell command, unless the end of
497 line is escaped with a backslash
499 in which case that line and the next are combined.
500 .\" The escaped newline is retained and passed to the shell, which
501 .\" normally ignores it.
502 .\" However, the tab at the beginning of the following line is removed.
503 If the first characters of the command are any combination of
508 the command is treated specially.
511 causes the command not to be echoed before it is executed.
514 causes the command to be executed even when
517 This is similar to the effect of the .MAKE special source,
518 except that the effect can be limited to a single line of a script.
521 in compatibility mode
522 causes any non-zero exit status of the command line to be ignored.
526 is run in jobs mode with
528 the entire script for the target is fed to a
529 single instance of the shell.
530 In compatibility (non-jobs) mode, each command is run in a separate process.
531 If the command contains any shell meta characters
532 .Pq Ql #=|^(){};&<>*?[]:$`\e\en
533 it will be passed to the shell; otherwise
535 will attempt direct execution.
536 If a line starts with
538 and the shell has ErrCtl enabled then failure of the command line
539 will be ignored as in compatibility mode.
542 affects the entire job;
543 the script will stop at the first command line that fails,
544 but the target will not be deemed to have failed.
546 Makefiles should be written so that the mode of
548 operation does not change their behavior.
549 For example, any command which needs to use
553 without potentially changing the directory for subsequent commands
554 should be put in parentheses so it executes in a subshell.
555 To force the use of one shell, escape the line breaks so as to make
556 the whole script one command.
558 .Bd -literal -offset indent
559 avoid-chdir-side-effects:
560 @echo Building $@ in `pwd`
561 @(cd ${.CURDIR} && ${MAKE} $@)
564 ensure-one-shell-regardless-of-mode:
565 @echo Building $@ in `pwd`; \e
566 (cd ${.CURDIR} && ${MAKE} $@); \e
576 before executing any targets, each child process
577 starts with that as its current working directory.
578 .Sh VARIABLE ASSIGNMENTS
579 Variables in make are much like variables in the shell, and, by tradition,
580 consist of all upper-case letters.
581 .Ss Variable assignment modifiers
582 The five operators that can be used to assign values to variables are as
586 Assign the value to the variable.
587 Any previous value is overridden.
589 Append the value to the current value of the variable.
591 Assign the value to the variable if it is not already defined.
593 Assign with expansion, i.e. expand the value before assigning it
595 Normally, expansion is not done until the variable is referenced.
597 References to undefined variables are
600 This can cause problems when variable modifiers are used.
602 Expand the value and pass it to the shell for execution and assign
603 the result to the variable.
604 Any newlines in the result are replaced with spaces.
607 Any white-space before the assigned
609 is removed; if the value is being appended, a single space is inserted
610 between the previous contents of the variable and the appended value.
612 Variables are expanded by surrounding the variable name with either
617 and preceding it with
620 If the variable name contains only a single letter, the surrounding
621 braces or parentheses are not required.
622 This shorter form is not recommended.
624 If the variable name contains a dollar, then the name itself is expanded first.
625 This allows almost arbitrary variable names, however names containing dollar,
626 braces, parentheses, or whitespace are really best avoided!
628 If the result of expanding a variable contains a dollar sign
630 the string is expanded again.
632 Variable substitution occurs at three distinct times, depending on where
633 the variable is being used.
636 Variables in dependency lines are expanded as the line is read.
638 Variables in shell commands are expanded when the shell command is
642 loop index variables are expanded on each loop iteration.
643 Note that other variables are not expanded inside loops so
644 the following example code:
645 .Bd -literal -offset indent
659 .Bd -literal -offset indent
664 Because while ${a} contains
666 after the loop is executed, ${b}
671 since after the loop completes ${j} contains
675 The four different classes of variables (in order of increasing precedence)
678 .It Environment variables
679 Variables defined as part of
683 Variables defined in the makefile or in included makefiles.
684 .It Command line variables
685 Variables defined as part of the command line.
687 Variables that are defined specific to a certain target.
690 Local variables are all built in and their values vary magically from
692 It is not currently possible to define new local variables.
693 The seven local variables are as follows:
694 .Bl -tag -width ".ARCHIVE" -offset indent
696 The list of all sources for this target; also known as
699 The name of the archive file; also known as
702 In suffix-transformation rules, the name/path of the source from which the
703 target is to be transformed (the
705 source); also known as
707 It is not defined in explicit rules.
709 The name of the archive member; also known as
712 The list of sources for this target that were deemed out-of-date; also
716 The file prefix of the target, containing only the file portion, no suffix
717 or preceding directory components; also known as
719 The suffix must be one of the known suffixes declared with
721 or it will not be recognized.
723 The name of the target; also known as
725 For compatibility with other makes this is an alias for
727 in archive member rules.
739 are permitted for backward
740 compatibility with historical makefiles and legacy POSIX make and are
743 Variants of these variables with the punctuation followed immediately by
749 are legacy forms equivalent to using the
754 These forms are accepted for compatibility with
756 makefiles and POSIX but are not recommended.
758 Four of the local variables may be used in sources on dependency lines
759 because they expand to the proper value for each target on the line.
766 .Ss Additional built-in variables
769 sets or knows about the following variables:
770 .Bl -tag -width .MAKEOVERRIDES
776 expands to a single dollar
779 The list of all targets encountered in the Makefile.
781 Makefile parsing, lists only those targets encountered thus far.
783 A path to the directory where
786 Refer to the description of
789 .It Va .INCLUDEDFROMDIR
790 The directory of the file this Makefile was included from.
791 .It Va .INCLUDEDFROMFILE
792 The filename of the file this Makefile was included from.
803 The preferred variable to use is the environment variable
805 because it is more compatible with other versions of
807 and cannot be confused with the special target with the same name.
808 .It Va .MAKE.ALWAYS_PASS_JOB_QUEUE
811 whether to pass the descriptors of the job token queue
812 even if the target is not tagged with
816 for backwards compatability with
819 .It Va .MAKE.DEPENDFILE
820 Names the makefile (default
822 from which generated dependencies are read.
823 .It Va .MAKE.EXPAND_VARIABLES
824 A boolean that controls the default behavior of the
827 If true, variable values printed with
829 are fully expanded; if false, the raw variable contents (which may
830 include additional unexpanded variable references) are shown.
831 .It Va .MAKE.EXPORTED
832 The list of variables exported by
838 .It Va .MAKE.JOB.PREFIX
843 then output for each target is prefixed with a token
845 the first part of which can be controlled via
846 .Va .MAKE.JOB.PREFIX .
849 is empty, no token is printed.
852 .Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}]
853 would produce tokens like
854 .Ql ---make[1234] target ---
855 making it easier to track the degree of parallelism being achieved.
857 The environment variable
859 may contain anything that
863 Anything specified on
865 command line is appended to the
867 variable which is then
868 entered into the environment for all programs which
872 The recursion depth of
874 The initial instance of
876 will be 0, and an incremented value is put into the environment
877 to be seen by the next generation.
878 This allows tests like:
879 .Li .if ${.MAKE.LEVEL} == 0
880 to protect things which should only be evaluated in the initial instance of
882 .It Va .MAKE.MAKEFILE_PREFERENCE
883 The ordered list of makefile names
890 .It Va .MAKE.MAKEFILES
891 The list of makefiles read by
893 which is useful for tracking dependencies.
894 Each makefile is recorded only once, regardless of the number of times read.
896 Processed after reading all makefiles.
897 Can affect the mode that
900 It can contain a number of keywords:
901 .Bl -hang -width missing-filemon=bf.
911 into "meta" mode, where meta files are created for each target
912 to capture the command run, the output generated and if
914 is available, the system calls which are of interest to
916 The captured output can be very useful when diagnosing errors.
917 .It Pa curdirOk= Ar bf
920 will not create .meta files in
922 This can be overridden by setting
924 to a value which represents True.
925 .It Pa missing-meta= Ar bf
928 is True, then a missing .meta file makes the target out-of-date.
929 .It Pa missing-filemon= Ar bf
932 is True, then missing filemon data makes the target out-of-date.
937 For debugging, it can be useful to include the environment
940 If in "meta" mode, print a clue about the target being built.
941 This is useful if the build is otherwise running silently.
942 The message printed the value of:
943 .Va .MAKE.META.PREFIX .
945 Some makefiles have commands which are simply not stable.
946 This keyword causes them to be ignored for
947 determining whether a target is out of date in "meta" mode.
953 is True, when a .meta file is created, mark the target
956 .It Va .MAKE.META.BAILIWICK
957 In "meta" mode, provides a list of prefixes which
958 match the directories controlled by
960 If a file that was generated outside of
962 but within said bailiwick is missing,
963 the current target is considered out-of-date.
964 .It Va .MAKE.META.CREATED
965 In "meta" mode, this variable contains a list of all the meta files
967 If not empty, it can be used to trigger processing of
968 .Va .MAKE.META.FILES .
969 .It Va .MAKE.META.FILES
970 In "meta" mode, this variable contains a list of all the meta files
971 used (updated or not).
972 This list can be used to process the meta files to extract dependency
974 .It Va .MAKE.META.IGNORE_PATHS
975 Provides a list of path prefixes that should be ignored;
976 because the contents are expected to change over time.
977 The default list includes:
978 .Ql Pa /dev /etc /proc /tmp /var/run /var/tmp
979 .It Va .MAKE.META.IGNORE_PATTERNS
980 Provides a list of patterns to match against pathnames.
981 Ignore any that match.
982 .It Va .MAKE.META.IGNORE_FILTER
983 Provides a list of variable modifiers to apply to each pathname.
984 Ignore if the expansion is an empty string.
985 .It Va .MAKE.META.PREFIX
986 Defines the message printed for each meta file updated in "meta verbose" mode.
987 The default value is:
988 .Dl Building ${.TARGET:H:tA}/${.TARGET:T}
989 .It Va .MAKEOVERRIDES
990 This variable is used to record the names of variables assigned to
991 on the command line, so that they may be exported as part of
993 This behavior can be disabled by assigning an empty value to
994 .Ql Va .MAKEOVERRIDES
996 Extra variables can be exported from a makefile
997 by appending their names to
998 .Ql Va .MAKEOVERRIDES .
1000 is re-exported whenever
1001 .Ql Va .MAKEOVERRIDES
1003 .It Va .MAKE.PATH_FILEMON
1008 support, this is set to the path of the device node.
1009 This allows makefiles to test for this support.
1014 The parent process-id of
1016 .It Va .MAKE.SAVE_DOLLARS
1017 value should be a boolean that controls whether
1019 are preserved when doing
1022 The default is false, for backwards compatibility.
1023 Set to true for compatability with other makes.
1028 per normal evaluation rules.
1029 .It Va MAKE_PRINT_VAR_ON_ERROR
1032 stops due to an error, it sets
1033 .Ql Va .ERROR_TARGET
1034 to the name of the target that failed,
1036 to the commands of the failed target,
1037 and in "meta" mode, it also sets
1042 .Ql Va .ERROR_META_FILE
1043 to the path of the meta file (if any) describing the failed target.
1044 It then prints its name and the value of
1046 as well as the value of any variables named in
1047 .Ql Va MAKE_PRINT_VAR_ON_ERROR .
1049 This variable is simply assigned a newline character as its value.
1050 This allows expansions using the
1052 modifier to put a newline between
1053 iterations of the loop rather than a space.
1054 For example, the printing of
1055 .Ql Va MAKE_PRINT_VAR_ON_ERROR
1056 could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}.
1058 A path to the directory where the targets are built.
1059 Its value is determined by trying to
1061 to the following directories in order and using the first match:
1064 .Ev ${MAKEOBJDIRPREFIX}${.CURDIR}
1067 .Ql Ev MAKEOBJDIRPREFIX
1068 is set in the environment or on the command line.)
1074 is set in the environment or on the command line.)
1076 .Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE}
1078 .Ev ${.CURDIR} Ns Pa /obj
1080 .Pa /usr/obj/ Ns Ev ${.CURDIR}
1085 Variable expansion is performed on the value before it's used,
1086 so expressions such as
1087 .Dl ${.CURDIR:S,^/usr/src,/var/obj,}
1089 This is especially useful with
1093 may be modified in the makefile via the special target
1099 to the specified directory if it exists, and set
1103 to that directory before executing any targets.
1106 A path to the directory of the current
1110 The basename of the current
1115 are both set only while the
1118 If you want to retain their current values, assign them to a variable
1119 using assignment with expansion:
1122 A variable that represents the list of directories that
1124 will search for files.
1125 The search list should be updated using the target
1127 rather than the variable.
1129 Alternate path to the current directory.
1133 to the canonical path given by
1135 However, if the environment variable
1137 is set and gives a path to the current directory, then
1144 This behavior is disabled if
1145 .Ql Ev MAKEOBJDIRPREFIX
1148 contains a variable transform.
1150 is set to the value of
1152 for all programs which
1156 The pathname of the shell used to run target scripts.
1159 The list of targets explicitly specified on the command line, if any.
1163 lists of directories that
1165 will search for files.
1166 The variable is supported for compatibility with old make programs only,
1171 .Ss Variable modifiers
1172 Variable expansion may be modified to select or modify each word of the
1175 is white-space delimited sequence of characters).
1176 The general format of a variable expansion is as follows:
1178 .Dl ${variable[:modifier[:...]]}
1180 Each modifier begins with a colon,
1181 which may be escaped with a backslash
1184 A set of modifiers can be specified via a variable, as follows:
1186 .Dl modifier_variable=modifier[:...]
1187 .Dl ${variable:${modifier_variable}[:...]}
1189 In this case the first modifier in the modifier_variable does not
1190 start with a colon, since that must appear in the referencing
1192 If any of the modifiers in the modifier_variable contain a dollar sign
1194 these must be doubled to avoid early expansion.
1196 The supported modifiers are:
1199 Replaces each word in the variable with its suffix.
1201 Replaces each word in the variable with everything but the last component.
1202 .It Cm \&:M Ns Ar pattern
1203 Selects only those words that match
1205 The standard shell wildcard characters
1212 The wildcard characters may be escaped with a backslash
1214 As a consequence of the way values are split into words, matched,
1215 and then joined, a construct like
1217 will normalize the inter-word spacing, removing all leading and
1218 trailing space, and converting multiple consecutive spaces
1221 .It Cm \&:N Ns Ar pattern
1222 This is identical to
1224 but selects all words which do not match
1227 Orders every word in variable alphabetically.
1229 Orders every word in variable in reverse alphabetical order.
1231 Shuffles the words in variable.
1232 The results will be different each time you are referring to the
1233 modified variable; use the assignment with expansion
1235 to prevent such behavior.
1237 .Bd -literal -offset indent
1238 LIST= uno due tre quattro
1239 RANDOM_LIST= ${LIST:Ox}
1240 STATIC_RANDOM_LIST:= ${LIST:Ox}
1243 @echo "${RANDOM_LIST}"
1244 @echo "${RANDOM_LIST}"
1245 @echo "${STATIC_RANDOM_LIST}"
1246 @echo "${STATIC_RANDOM_LIST}"
1248 may produce output similar to:
1249 .Bd -literal -offset indent
1256 Quotes every shell meta-character in the variable, so that it can be passed
1257 safely to the shell.
1259 Quotes every shell meta-character in the variable, and also doubles
1261 characters so that it can be passed
1262 safely through recursive invocations of
1264 This is equivalent to:
1265 .Sq \&:S/\e\&$/&&/g:Q .
1267 Replaces each word in the variable with everything but its suffix.
1268 .It Cm \&:range[=count]
1269 The value is an integer sequence representing the words of the original
1270 value, or the supplied
1272 .It Cm \&:gmtime[=utc]
1273 The value is a format string for
1279 value is not provided or is 0, the current time is used.
1281 Computes a 32-bit hash of the value and encode it as hex digits.
1282 .It Cm \&:localtime[=utc]
1283 The value is a format string for
1289 value is not provided or is 0, the current time is used.
1291 Attempts to convert variable to an absolute path using
1293 if that fails, the value is unchanged.
1295 Converts variable to lower-case letters.
1296 .It Cm \&:ts Ns Ar c
1297 Words in the variable are normally separated by a space on expansion.
1298 This modifier sets the separator to the character
1302 is omitted, then no separator is used.
1303 The common escapes (including octal numeric codes) work as expected.
1305 Converts variable to upper-case letters.
1307 Causes the value to be treated as a single word
1308 (possibly containing embedded white space).
1312 Causes the value to be treated as a sequence of
1313 words delimited by white space.
1317 .It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW
1319 Modifies the first occurrence of
1321 in each word of the variable's value, replacing it with
1325 is appended to the last delimiter of the pattern, all occurrences
1326 in each word are replaced.
1329 is appended to the last delimiter of the pattern, only the first occurrence
1333 is appended to the last delimiter of the pattern,
1334 then the value is treated as a single word
1335 (possibly containing embedded white space).
1341 is anchored at the beginning of each word.
1344 ends with a dollar sign
1346 it is anchored at the end of each word.
1357 Any character may be used as a delimiter for the parts of the modifier
1359 The anchoring, ampersand and delimiter characters may be escaped with a
1363 Variable expansion occurs in the normal fashion inside both
1367 with the single exception that a backslash is used to prevent the expansion
1370 not a preceding dollar sign as is usual.
1372 .It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW
1376 modifier is just like the
1378 modifier except that the old and new strings, instead of being
1379 simple strings, are an extended regular expression (see
1387 Normally, the first occurrence of the pattern
1389 in each word of the value is substituted with
1393 modifier causes the substitution to apply to at most one word; the
1395 modifier causes the substitution to apply to as many instances of the
1398 as occur in the word or words it is found in; the
1400 modifier causes the value to be treated as a single word
1401 (possibly containing embedded white space).
1409 are subjected to variable expansion before being parsed as
1410 regular expressions.
1412 Replaces each word in the variable with its last path component.
1414 Removes adjacent duplicate words (like
1417 .It Cm \&:\&? Ar true_string Cm \&: Ar false_string
1419 If the variable name (not its value), when parsed as a .if conditional
1420 expression, evaluates to true, return as its value the
1422 otherwise return the
1424 Since the variable name is used as the expression, \&:\&? must be the
1425 first modifier after the variable name itself - which will, of course,
1426 usually contain variable expansions.
1427 A common error is trying to use expressions like
1428 .Dl ${NUMBERS:M42:?match:no}
1429 which actually tests defined(NUMBERS),
1430 to determine if any words match "42" you need to use something like:
1431 .Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} .
1432 .It Ar :old_string=new_string
1435 style variable substitution.
1436 It must be the last modifier specified.
1441 do not contain the pattern matching character
1443 then it is assumed that they are
1444 anchored at the end of each word, so only suffixes or entire
1445 words may be replaced.
1454 contains the pattern matching character
1458 matches, then the result is the
1462 contains the pattern matching character
1464 then it is not treated specially and it is printed as a literal
1467 If there is more than one pattern matching character
1473 only the first instance is treated specially (as the pattern character);
1474 all subsequent instances are treated as regular characters.
1476 Variable expansion occurs in the normal fashion inside both
1480 with the single exception that a backslash is used to prevent the
1481 expansion of a dollar sign
1483 not a preceding dollar sign as is usual.
1485 .It Cm \&:@ Ar temp Cm @ Ar string Cm @
1487 This is the loop expansion mechanism from the OSF Development
1488 Environment (ODE) make.
1491 loops, expansion occurs at the time of reference.
1494 to each word in the variable and evaluates
1496 The ODE convention is that
1498 should start and end with a period.
1500 .Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
1502 However a single character variable is often more readable:
1503 .Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
1505 Saves the current variable value in
1509 for later reference.
1511 .Bd -literal -offset indent
1512 M_cmpv.units = 1 1000 1000000
1513 M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \&\\
1514 \\* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh
1516 .Dv .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}}
1521 is used to save the result of the
1523 modifier which is later referenced using the index values from
1525 .It Cm \&:U Ns Ar newval
1526 If the variable is undefined,
1529 If the variable is defined, the existing value is returned.
1530 This is another ODE make feature.
1531 It is handy for setting per-target CFLAGS for instance:
1532 .Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
1533 If a value is only required if the variable is undefined, use:
1534 .Dl ${VAR:D:Unewval}
1535 .It Cm \&:D Ns Ar newval
1536 If the variable is defined,
1540 The name of the variable is the value.
1542 The path of the node which has the same name as the variable
1544 If no such node exists or its path is null, then the
1545 name of the variable is used.
1546 In order for this modifier to work, the name (node) must at least have
1547 appeared on the rhs of a dependency.
1549 .It Cm \&:\&! Ar cmd Cm \&!
1551 The output of running
1555 If the variable is non-empty it is run as a command and the output
1556 becomes the new value.
1557 .It Cm \&::= Ns Ar str
1558 The variable is assigned the value
1561 This modifier and its variations are useful in
1562 obscure situations such as wanting to set a variable when shell commands
1564 These assignment modifiers always expand to
1565 nothing, so if appearing in a rule line by themselves should be
1566 preceded with something to keep
1572 helps avoid false matches with the
1576 modifier and since substitution always occurs the
1578 form is vaguely appropriate.
1579 .It Cm \&::?= Ns Ar str
1582 but only if the variable does not already have a value.
1583 .It Cm \&::+= Ns Ar str
1587 .It Cm \&::!= Ns Ar cmd
1588 Assign the output of
1591 .It Cm \&:\&[ Ns Ar range Ns Cm \&]
1592 Selects one or more words from the value,
1593 or performs other operations related to the way in which the
1594 value is divided into words.
1596 Ordinarily, a value is treated as a sequence of words
1597 delimited by white space.
1598 Some modifiers suppress this behavior,
1599 causing a value to be treated as a single word
1600 (possibly containing embedded white space).
1601 An empty value, or a value that consists entirely of white-space,
1602 is treated as a single word.
1603 For the purposes of the
1605 modifier, the words are indexed both forwards using positive integers
1606 (where index 1 represents the first word),
1607 and backwards using negative integers
1608 (where index \-1 represents the last word).
1612 is subjected to variable expansion, and the expanded result is
1613 then interpreted as follows:
1614 .Bl -tag -width index
1617 Selects a single word from the value.
1619 .It Ar start Ns Cm \&.. Ns Ar end
1620 Selects all words from
1627 selects all words from the second word to the last word.
1632 then the words are output in reverse order.
1635 selects all the words from last to first.
1636 If the list is already ordered, then this effectively reverses
1637 the list, but it is more efficient to use
1640 .Ql Cm \&:O:[-1..1] .
1643 Causes subsequent modifiers to treat the value as a single word
1644 (possibly containing embedded white space).
1645 Analogous to the effect of
1654 Causes subsequent modifiers to treat the value as a sequence of words
1655 delimited by white space.
1656 Analogous to the effect of
1661 Returns the number of words in the value.
1664 .Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
1665 Makefile inclusion, conditional structures and for loops reminiscent
1666 of the C programming language are provided in
1668 All such structures are identified by a line beginning with a single
1672 Files are included with either
1673 .Cm \&.include \&< Ns Ar file Ns Cm \&>
1675 .Cm \&.include \&\*q Ns Ar file Ns Cm \&\*q .
1676 Variables between the angle brackets or double quotes are expanded
1677 to form the file name.
1678 If angle brackets are used, the included makefile is expected to be in
1679 the system makefile directory.
1680 If double quotes are used, the including makefile's directory and any
1681 directories specified using the
1683 option are searched before the system
1685 For compatibility with other versions of
1687 .Ql include file ...
1690 If the include statement is written as
1694 then errors locating and/or opening include files are ignored.
1696 If the include statement is written as
1698 not only are errors locating and/or opening include files ignored,
1699 but stale dependencies within the included file will be ignored
1701 .Va .MAKE.DEPENDFILE .
1703 Conditional expressions are also preceded by a single dot as the first
1704 character of a line.
1705 The possible conditionals are as follows:
1707 .It Ic .error Ar message
1708 The message is printed along with the name of the makefile and line number,
1711 will exit immediately.
1712 .It Ic .export Ar variable ...
1713 Export the specified global variable.
1714 If no variable list is provided, all globals are exported
1715 except for internal variables (those that start with
1717 This is not affected by the
1719 flag, so should be used with caution.
1720 For compatibility with other
1723 .Ql export variable=value
1726 Appending a variable name to
1728 is equivalent to exporting a variable.
1729 .It Ic .export-env Ar variable ...
1732 except that the variable is not appended to
1733 .Va .MAKE.EXPORTED .
1734 This allows exporting a value to the environment which is different from that
1738 .It Ic .export-literal Ar variable ...
1741 except that variables in the value are not expanded.
1742 .It Ic .info Ar message
1743 The message is printed along with the name of the makefile and line number.
1744 .It Ic .undef Ar variable
1745 Un-define the specified global variable.
1746 Only global variables may be un-defined.
1747 .It Ic .unexport Ar variable ...
1750 The specified global
1752 will be removed from
1753 .Va .MAKE.EXPORTED .
1754 If no variable list is provided, all globals are unexported,
1758 .It Ic .unexport-env
1759 Unexport all globals previously exported and
1760 clear the environment inherited from the parent.
1761 This operation will cause a memory leak of the original environment,
1762 so should be used sparingly.
1765 being 0, would make sense.
1766 Also note that any variables which originated in the parent environment
1767 should be explicitly preserved if desired.
1769 .Bd -literal -offset indent
1770 .Li .if ${.MAKE.LEVEL} == 0
1777 Would result in an environment containing only
1779 which is the minimal useful environment.
1782 will also be pushed into the new environment.
1783 .It Ic .warning Ar message
1784 The message prefixed by
1786 is printed along with the name of the makefile and line number.
1787 .It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ...
1788 Test the value of an expression.
1789 .It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1790 Test the value of a variable.
1791 .It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1792 Test the value of a variable.
1793 .It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1794 Test the target being built.
1795 .It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ...
1796 Test the target being built.
1798 Reverse the sense of the last conditional.
1799 .It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ...
1804 .It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1809 .It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1814 .It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1819 .It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1825 End the body of the conditional.
1830 may be any one of the following:
1831 .Bl -tag -width "Cm XX"
1837 of higher precedence than
1843 will only evaluate a conditional as far as is necessary to determine
1845 Parentheses may be used to change the order of evaluation.
1846 The boolean operator
1848 may be used to logically negate an entire
1850 It is of higher precedence than
1855 may be any of the following:
1856 .Bl -tag -width defined
1858 Takes a variable name as an argument and evaluates to true if the variable
1861 Takes a target name as an argument and evaluates to true if the target
1862 was specified as part of
1864 command line or was declared the default target (either implicitly or
1867 before the line containing the conditional.
1869 Takes a variable, with possible modifiers, and evaluates to true if
1870 the expansion of the variable would result in an empty string.
1872 Takes a file name as an argument and evaluates to true if the file exists.
1873 The file is searched for on the system search path (see
1876 Takes a target name as an argument and evaluates to true if the target
1879 Takes a target name as an argument and evaluates to true if the target
1880 has been defined and has commands associated with it.
1884 may also be an arithmetic or string comparison.
1885 Variable expansion is
1886 performed on both sides of the comparison, after which the integral
1887 values are compared.
1888 A value is interpreted as hexadecimal if it is
1889 preceded by 0x, otherwise it is decimal; octal numbers are not supported.
1890 The standard C relational operators are all supported.
1892 variable expansion, either the left or right hand side of a
1896 operator is not an integral value, then
1897 string comparison is performed between the expanded
1899 If no relational operator is given, it is assumed that the expanded
1900 variable is being compared against 0, or an empty string in the case
1901 of a string comparison.
1905 is evaluating one of these conditional expressions, and it encounters
1906 a (white-space separated) word it doesn't recognize, either the
1910 expression is applied to it, depending on the form of the conditional.
1918 expression is applied.
1919 Similarly, if the form is
1925 expression is applied.
1927 If the conditional evaluates to true the parsing of the makefile continues
1929 If it evaluates to false, the following lines are skipped.
1930 In both cases this continues until a
1936 For loops are typically used to apply a set of rules to a list of files.
1937 The syntax of a for loop is:
1939 .Bl -tag -compact -width Ds
1940 .It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression
1947 is evaluated, it is split into words.
1948 On each iteration of the loop, one word is taken and assigned to each
1952 are substituted into the
1954 inside the body of the for loop.
1955 The number of words must come out even; that is, if there are three
1956 iteration variables, the number of words provided must be a multiple
1959 Comments begin with a hash
1961 character, anywhere but in a shell
1962 command line, and continue to the end of an unescaped new line.
1963 .Sh SPECIAL SOURCES (ATTRIBUTES)
1964 .Bl -tag -width .IGNOREx
1966 Target is never out of date, but always execute commands anyway.
1968 Ignore any errors from the commands associated with this target, exactly
1969 as if they all were preceded by a dash
1971 .\" .It Ic .INVISIBLE
1976 Mark all sources of this target as being up-to-date.
1978 Execute the commands associated with this target even if the
1982 options were specified.
1983 Normally used to mark recursive
1986 Create a meta file for the target, even if it is flagged as
1991 Usage in conjunction with
1993 is the most likely case.
1994 In "meta" mode, the target is out-of-date if the meta file is missing.
1996 Do not create a meta file for the target.
1997 Meta files are also not created for
2004 Ignore differences in commands when deciding if target is out of date.
2005 This is useful if the command contains a value which always changes.
2006 If the number of commands change, though, the target will still be out of date.
2007 The same effect applies to any command line that uses the variable
2009 which can be used for that purpose even when not otherwise needed or desired:
2010 .Bd -literal -offset indent
2012 skip-compare-for-some:
2013 @echo this will be compared
2014 @echo this will not ${.OODATE:M.NOMETA_CMP}
2015 @echo this will also be compared
2020 pattern suppresses any expansion of the unwanted variable.
2022 Do not search for the target in the directories specified by
2027 selects the first target it encounters as the default target to be built
2028 if no target was specified.
2029 This source prevents this target from being selected.
2031 If a target is marked with this attribute and
2033 can't figure out how to create it, it will ignore this fact and assume
2034 the file isn't needed or already exists.
2037 correspond to an actual file; it is always considered to be out of date,
2038 and will not be created with the
2041 Suffix-transformation rules are not applied to
2047 is interrupted, it normally removes any partially made targets.
2048 This source prevents the target from being removed.
2053 Do not echo any of the commands associated with this target, exactly
2054 as if they all were preceded by an at sign
2057 Turn the target into
2060 When the target is used as a source for another target, the other target
2061 acquires the commands, sources, and attributes (except for
2065 If the target already has commands, the
2067 target's commands are appended
2074 target commands to the target.
2078 appears in a dependency line, the sources that precede it are
2079 made before the sources that succeed it in the line.
2080 Since the dependents of files are not made until the file itself
2081 could be made, this also stops the dependents being built unless they
2082 are needed for another branch of the dependency tree.
2095 the output is always
2101 The ordering imposed by
2103 is only relevant for parallel makes.
2106 Special targets may not be included with other targets, i.e. they must be
2107 the only target specified.
2108 .Bl -tag -width .BEGINx
2110 Any command lines attached to this target are executed before anything
2115 rule for any target (that was used only as a
2118 can't figure out any other way to create.
2119 Only the shell script is used.
2122 variable of a target that inherits
2125 to the target's own name.
2126 .It Ic .DELETE_ON_ERROR
2127 If this target is present in the makefile, it globally causes make to
2128 delete targets whose commands fail.
2129 (By default, only targets whose commands are interrupted during
2130 execution are deleted.
2131 This is the historical behavior.)
2132 This setting can be used to help prevent half-finished or malformed
2133 targets from being left around and corrupting future rebuilds.
2135 Any command lines attached to this target are executed after everything
2138 Any command lines attached to this target are executed when another target fails.
2141 variable is set to the target that failed.
2143 .Ic MAKE_PRINT_VAR_ON_ERROR .
2145 Mark each of the sources with the
2148 If no sources are specified, this is the equivalent of specifying the
2154 is interrupted, the commands for this target will be executed.
2156 If no target is specified when
2158 is invoked, this target will be built.
2160 This target provides a way to specify flags for
2162 when the makefile is used.
2163 The flags are as if typed to the shell, though the
2167 .\" XXX: NOT YET!!!!
2168 .\" .It Ic .NOTPARALLEL
2169 .\" The named targets are executed in non parallel mode.
2170 .\" If no targets are
2171 .\" specified, then all targets are executed in non parallel mode.
2175 attribute to any specified sources.
2177 Disable parallel mode.
2181 for compatibility with other pmake variants.
2183 The source is a new value for
2189 to it and update the value of
2192 The named targets are made in sequence.
2193 This ordering does not add targets to the list of targets to be made.
2194 Since the dependents of a target do not get built until the target itself
2195 could be built, unless
2197 is built by another part of the dependency graph,
2198 the following is a dependency loop:
2204 The ordering imposed by
2206 is only relevant for parallel makes.
2207 .\" XXX: NOT YET!!!!
2208 .\" .It Ic .PARALLEL
2209 .\" The named targets are executed in parallel mode.
2210 .\" If no targets are
2211 .\" specified, then all targets are executed in parallel mode.
2213 The sources are directories which are to be searched for files not
2214 found in the current directory.
2215 If no sources are specified, any previously specified directories are
2217 If the source is the special
2219 target, then the current working
2220 directory is searched last.
2221 .It Ic .PATH. Ns Va suffix
2224 but applies only to files with a particular suffix.
2225 The suffix must have been previously declared with
2230 attribute to any specified sources.
2234 attribute to any specified sources.
2235 If no sources are specified, the
2237 attribute is applied to every
2242 will use to execute commands.
2243 The sources are a set of
2246 .Bl -tag -width hasErrCtls
2248 This is the minimal specification, used to select one of the built-in
2255 Specifies the path to the shell.
2257 Indicates whether the shell supports exit on error.
2259 The command to turn on error checking.
2261 The command to disable error checking.
2263 The command to turn on echoing of commands executed.
2265 The command to turn off echoing of commands executed.
2267 The output to filter after issuing the
2270 It is typically identical to
2273 The flag to pass the shell to enable error checking.
2275 The flag to pass the shell to enable command echoing.
2277 The string literal to pass the shell that results in a single newline
2278 character when used outside of any quoting characters.
2282 \&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e
2283 check="set \-e" ignore="set +e" \e
2284 echo="set \-v" quiet="set +v" filter="set +v" \e
2285 echoFlag=v errFlag=e newline="'\en'"
2290 attribute to any specified sources.
2291 If no sources are specified, the
2293 attribute is applied to every
2294 command in the file.
2296 This target gets run when a dependency file contains stale entries, having
2298 set to the name of that dependency file.
2300 Each source specifies a suffix to
2302 If no sources are specified, any previously specified suffixes are deleted.
2303 It allows the creation of suffix-transformation rules.
2309 cc \-o ${.TARGET} \-c ${.IMPSRC}
2314 uses the following environment variables, if they exist:
2320 .Ev MAKEOBJDIRPREFIX ,
2326 .Ev MAKEOBJDIRPREFIX
2329 may only be set in the environment or on the command line to
2331 and not as makefile variables;
2332 see the description of
2336 .Bl -tag -width /usr/share/mk -compact
2338 list of dependencies
2340 list of dependencies
2342 list of dependencies
2346 system makefile directory
2349 The basic make syntax is compatible between different versions of make;
2350 however the special variables, variable modifiers and conditionals are not.
2352 An incomplete list of changes in older versions of
2355 The way that .for loop variables are substituted changed after
2357 so that they still appear to be variable expansions.
2358 In particular this stops them being treated as syntax, and removes some
2359 obscure problems using them in .if statements.
2361 The way that parallel makes are scheduled changed in
2363 so that .ORDER and .WAIT apply recursively to the dependent nodes.
2364 The algorithms used may change again in the future.
2365 .Ss Other make dialects
2366 Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not
2367 support most of the features of
2369 as described in this manual.
2371 .Bl -bullet -offset indent
2377 declarations and most functionality pertaining to parallelization.
2378 (GNU make supports parallelization but lacks these features needed to
2379 control it effectively.)
2381 Directives, including for loops and conditionals and most of the
2382 forms of include files.
2383 (GNU make has its own incompatible and less powerful syntax for
2386 All built-in variables that begin with a dot.
2388 Most of the special sources and targets that begin with a dot,
2389 with the notable exception of
2395 Variable modifiers, except for the
2397 string substitution, which does not portably support globbing with
2399 and historically only works on declared suffixes.
2403 variable even in its short form; most makes support this functionality
2404 but its name varies.
2407 Some features are somewhat more portable, such as assignment with
2414 functionality is based on an older feature
2416 found in GNU make and many versions of SVR4 make; however,
2417 historically its behavior is too ill-defined (and too buggy) to rely
2424 variables are more or less universally portable, as is the
2427 Basic use of suffix rules (for files only in the current directory,
2428 not trying to chain transformations together, etc.) is also reasonably
2432 .Xr style.Makefile 5
2440 implementation is based on Adam De Boor's pmake program which was written
2441 for Sprite at Berkeley.
2442 It was designed to be a parallel distributed make running jobs on different
2443 machines using a daemon called
2446 Historically the target/dependency
2448 has been used to FoRCe rebuilding (since the target/dependency
2449 does not exist... unless someone creates an
2455 syntax is difficult to parse without actually acting on the data.
2456 For instance, finding the end of a variable's use should involve scanning
2457 each of the modifiers, using the correct terminator for each field.
2460 just counts {} and () in order to find the end of a variable expansion.
2462 There is no way of escaping a space character in a filename.