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30 .\" from: @(#)make.1 8.4 (Berkeley) 3/19/94
37 .Nd maintain program dependencies
55 is a program designed to simplify the maintenance of other programs.
56 Its input is a list of specifications as to the files upon which programs
57 and other files depend.
60 makefile option is given,
66 in order to find the specifications.
69 exists, it is read (see
72 This manual page is intended as a reference document only.
73 For a more thorough description of
75 and makefiles, please refer to
76 .%T "PMake \- A Tutorial" .
79 will prepend the contents of the
81 environment variable to the command line arguments before parsing them.
83 The options are as follows:
86 Try to be backwards compatible by executing a single shell per command and
87 by executing the commands to make the sources of a dependency line in sequence.
91 before reading the makefiles or doing anything else.
94 options are specified, each is interpreted relative to the previous one:
95 .Fl C Pa / Fl C Pa etc
101 to be 1, in the global context.
103 Turn on debugging, and specify which portions of
105 are to print debugging information.
106 Unless the flags are preceded by
108 they are added to the
110 environment variable and will be processed by any child make processes.
111 By default, debugging information is printed to standard error,
112 but this can be changed using the
115 The debugging output is always unbuffered; in addition, if debugging
116 is enabled but debugging output is not directed to standard output,
117 then the standard output is line buffered.
119 is one or more of the following:
122 Print all possible debugging information;
123 equivalent to specifying all of the debugging flags.
125 Print debugging information about archive searching and caching.
127 Print debugging information about current working directory.
129 Print debugging information about conditional evaluation.
131 Print debugging information about directory searching and caching.
133 Print debugging information about failed commands and targets.
134 .It Ar F Ns Oo Sy \&+ Oc Ns Ar filename
135 Specify where debugging output is written.
136 This must be the last flag, because it consumes the remainder of
138 If the character immediately after the
142 then the file will be opened in append mode;
143 otherwise the file will be overwritten.
148 then debugging output will be written to the
149 standard output or standard error output file descriptors respectively
152 option has no effect).
153 Otherwise, the output will be written to the named file.
154 If the file name ends
158 is replaced by the pid.
160 Print debugging information about loop evaluation.
162 Print the input graph before making anything.
164 Print the input graph after making everything, or before exiting
167 Print the input graph before exiting on error.
169 Print debugging information about running multiple shells.
171 Print commands in Makefiles regardless of whether or not they are prefixed by
173 or other "quiet" flags.
174 Also known as "loud" behavior.
176 Print debugging information about "meta" mode decisions about targets.
178 Print debugging information about making targets, including modification
181 Don't delete the temporary command scripts created when running commands.
182 These temporary scripts are created in the directory
185 environment variable, or in
189 is unset or set to the empty string.
190 The temporary scripts are created by
192 and have names of the form
195 This can create many files in
201 Print debugging information about makefile parsing.
203 Print debugging information about suffix-transformation rules.
205 Print debugging information about target list maintenance.
209 option to print raw values of variables.
211 Print debugging information about variable assignment.
213 Print entering and leaving directory messages, pre and post processing.
215 Run shell commands with
217 so the actual commands are printed as they are executed.
220 Specify that environment variables override macro assignments within
223 Specify a makefile to read instead of the default
229 standard input is read.
230 Multiple makefiles may be specified, and are read in the order specified.
231 .It Fl I Ar directory
232 Specify a directory in which to search for makefiles and included makefiles.
233 The system makefile directory (or directories, see the
235 option) is automatically included as part of this list.
237 Ignore non-zero exit of shell commands in the makefile.
238 Equivalent to specifying
240 before each command line in the makefile.
244 be specified by the user.
248 option is in use in a recursive build, this option is passed by a make
249 to child makes to allow all the make processes in the build to
250 cooperate to avoid overloading the system.
252 Specify the maximum number of jobs that
254 may have running at any one time.
255 The value is saved in
257 Turns compatibility mode off, unless the
259 flag is also specified.
260 When compatibility mode is off, all commands associated with a
261 target are executed in a single shell invocation as opposed to the
262 traditional one shell invocation per line.
263 This can break traditional scripts which change directories on each
264 command invocation and then expect to start with a fresh environment
266 It is more efficient to correct the scripts rather than turn backwards
269 Continue processing after errors are encountered, but only on those targets
270 that do not depend on the target whose creation caused the error.
271 .It Fl m Ar directory
272 Specify a directory in which to search for sys.mk and makefiles included
274 .Ao Ar file Ac Ns -style
278 option can be used multiple times to form a search path.
279 This path will override the default system include path: /usr/share/mk.
280 Furthermore the system include path will be appended to the search path used
282 .Qo Ar file Qc Ns -style
283 include statements (see the
287 If a file or directory name in the
291 environment variable) starts with the string
295 will search for the specified file or directory named in the remaining part
296 of the argument string.
297 The search starts with the current directory of
298 the Makefile and then works upward towards the root of the filesystem.
299 If the search is successful, then the resulting directory replaces the
304 If used, this feature allows
306 to easily search in the current source tree for customized sys.mk files
311 Display the commands that would have been executed, but do not
312 actually execute them unless the target depends on the .MAKE special
315 Display the commands which would have been executed, but do not
316 actually execute any of them; useful for debugging top-level makefiles
317 without descending into subdirectories.
319 Do not execute any commands, but exit 0 if the specified targets are
320 up-to-date and 1, otherwise.
322 Do not use the built-in rules specified in the system makefile.
324 Do not echo any commands as they are executed.
325 Equivalent to specifying
327 before each command line in the makefile.
328 .It Fl T Ar tracefile
332 append a trace record to
334 for each job started and completed.
336 Rather than re-building a target as specified in the makefile, create it
337 or update its modification time to make it appear up-to-date.
343 in the global context.
344 Do not build any targets.
345 Multiple instances of this option may be specified;
346 the variables will be printed one per line,
347 with a blank line for each null or undefined variable.
352 then the value will be expanded before printing.
354 Treat any warnings during makefile parsing as errors.
356 Don't export variables passed on the command line to the environment
358 Variables passed on the command line are still exported
361 environment variable.
362 This option may be useful on systems which have a small limit on the
363 size of command arguments.
364 .It Ar variable=value
365 Set the value of the variable
369 Normally, all values passed on the command line are also exported to
370 sub-makes in the environment.
373 flag disables this behavior.
374 Variable assignments should follow options for POSIX compatibility
375 but no ordering is enforced.
378 There are seven different types of lines in a makefile: file dependency
379 specifications, shell commands, variable assignments, include statements,
380 conditional directives, for loops, and comments.
382 In general, lines may be continued from one line to the next by ending
383 them with a backslash
385 The trailing newline character and initial whitespace on the following
386 line are compressed into a single space.
387 .Sh FILE DEPENDENCY SPECIFICATIONS
388 Dependency lines consist of one or more targets, an operator, and zero
390 This creates a relationship where the targets
393 and are usually created from them.
394 The exact relationship between the target and the source is determined
395 by the operator that separates them.
396 The three operators are as follows:
399 A target is considered out-of-date if its modification time is less than
400 those of any of its sources.
401 Sources for a target accumulate over dependency lines when this operator
403 The target is removed if
407 Targets are always re-created, but not until all sources have been
408 examined and re-created as necessary.
409 Sources for a target accumulate over dependency lines when this operator
411 The target is removed if
415 If no sources are specified, the target is always re-created.
416 Otherwise, a target is considered out-of-date if any of its sources has
417 been modified more recently than the target.
418 Sources for a target do not accumulate over dependency lines when this
420 The target will not be removed if
425 Targets and sources may contain the shell wildcard values
436 may only be used as part of the final
437 component of the target or source, and must be used to describe existing
441 need not necessarily be used to describe existing files.
442 Expansion is in directory order, not alphabetically as done in the shell.
444 Each target may have associated with it a series of shell commands, normally
445 used to create the target.
446 Each of the commands in this script
448 be preceded by a tab.
449 While any target may appear on a dependency line, only one of these
450 dependencies may be followed by a creation script, unless the
454 If the first characters of the command line are any combination of
459 the command is treated specially.
462 causes the command not to be echoed before it is executed.
465 causes the command to be executed even when
468 This is similar to the effect of the .MAKE special source,
469 except that the effect can be limited to a single line of a script.
472 causes any non-zero exit status of the command line to be ignored.
476 is run in jobs mode with
478 the entire script for the target is fed to a
479 single instance of the shell.
481 In compatibility (non-jobs) mode, each command is run in a separate process.
482 If the command contains any shell meta characters
483 .Pq Ql #=|^(){};&<>*?[]:$`\e\en
484 it will be passed to the shell, otherwise
486 will attempt direct execution.
494 before executing any targets, each child process
495 starts with that as its current working directory.
497 Makefiles should be written so that the mode of
499 operation does not change their behavior.
500 For example, any command which needs to use
504 without side-effect should be put in parenthesis:
505 .Bd -literal -offset indent
507 avoid-chdir-side-effects:
508 @echo Building $@ in `pwd`
509 @(cd ${.CURDIR} && ${.MAKE} $@)
512 ensure-one-shell-regardless-of-mode:
513 @echo Building $@ in `pwd`; \\
514 (cd ${.CURDIR} && ${.MAKE} $@); \\
517 .Sh VARIABLE ASSIGNMENTS
518 Variables in make are much like variables in the shell, and, by tradition,
519 consist of all upper-case letters.
520 .Ss Variable assignment modifiers
521 The five operators that can be used to assign values to variables are as
525 Assign the value to the variable.
526 Any previous value is overridden.
528 Append the value to the current value of the variable.
530 Assign the value to the variable if it is not already defined.
532 Assign with expansion, i.e. expand the value before assigning it
534 Normally, expansion is not done until the variable is referenced.
536 References to undefined variables are
539 This can cause problems when variable modifiers are used.
541 Expand the value and pass it to the shell for execution and assign
542 the result to the variable.
543 Any newlines in the result are replaced with spaces.
546 Any white-space before the assigned
548 is removed; if the value is being appended, a single space is inserted
549 between the previous contents of the variable and the appended value.
551 Variables are expanded by surrounding the variable name with either
556 and preceding it with
559 If the variable name contains only a single letter, the surrounding
560 braces or parentheses are not required.
561 This shorter form is not recommended.
563 If the variable name contains a dollar, then the name itself is expanded first.
564 This allows almost arbitrary variable names, however names containing dollar,
565 braces, parenthesis, or whitespace are really best avoided!
567 If the result of expanding a variable contains a dollar sign
569 the string is expanded again.
571 Variable substitution occurs at three distinct times, depending on where
572 the variable is being used.
575 Variables in dependency lines are expanded as the line is read.
577 Variables in shell commands are expanded when the shell command is
581 loop index variables are expanded on each loop iteration.
582 Note that other variables are not expanded inside loops so
583 the following example code:
584 .Bd -literal -offset indent
598 .Bd -literal -offset indent
603 Because while ${a} contains
605 after the loop is executed, ${b}
610 since after the loop completes ${j} contains
614 The four different classes of variables (in order of increasing precedence)
617 .It Environment variables
618 Variables defined as part of
622 Variables defined in the makefile or in included makefiles.
623 .It Command line variables
624 Variables defined as part of the command line.
626 Variables that are defined specific to a certain target.
627 The seven local variables are as follows:
628 .Bl -tag -width ".ARCHIVE"
630 The list of all sources for this target; also known as
633 The name of the archive file.
635 In suffix-transformation rules, the name/path of the source from which the
636 target is to be transformed (the
638 source); also known as
640 It is not defined in explicit rules.
642 The name of the archive member.
644 The list of sources for this target that were deemed out-of-date; also
648 The file prefix of the target, containing only the file portion, no suffix
649 or preceding directory components; also known as
652 The name of the target; also known as
663 are permitted for backward
664 compatibility with historical makefiles and are not recommended.
673 are permitted for compatibility with
675 makefiles and are not recommended.
677 Four of the local variables may be used in sources on dependency lines
678 because they expand to the proper value for each target on the line.
686 .Ss Additional built-in variables
689 sets or knows about the following variables:
690 .Bl -tag -width .MAKEOVERRIDES
696 expands to a single dollar
699 The list of all targets encountered in the Makefile.
701 Makefile parsing, lists only those targets encountered thus far.
703 A path to the directory where
706 Refer to the description of
709 .It Va .INCLUDEDFROMDIR
710 The directory of the file this Makefile was included from.
711 .It Va .INCLUDEDFROMFILE
712 The filename of the file this Makefile was included from.
723 The preferred variable to use is the environment variable
725 because it is more compatible with other versions of
727 and cannot be confused with the special target with the same name.
728 .It Va .MAKE.DEPENDFILE
729 Names the makefile (default
731 from which generated dependencies are read.
732 .It Va .MAKE.EXPAND_VARIABLES
733 A boolean that controls the default behavior of the
736 .It Va .MAKE.EXPORTED
737 The list of variables exported by
743 .It Va .MAKE.JOB.PREFIX
748 then output for each target is prefixed with a token
750 the first part of which can be controlled via
751 .Va .MAKE.JOB.PREFIX .
754 is empty, no token is printed.
757 .Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}]
758 would produce tokens like
759 .Ql ---make[1234] target ---
760 making it easier to track the degree of parallelism being achieved.
762 The environment variable
764 may contain anything that
768 Anything specified on
770 command line is appended to the
772 variable which is then
773 entered into the environment for all programs which
777 The recursion depth of
779 The initial instance of
781 will be 0, and an incremented value is put into the environment
782 to be seen by the next generation.
783 This allows tests like:
784 .Li .if ${.MAKE.LEVEL} == 0
785 to protect things which should only be evaluated in the initial instance of
787 .It Va .MAKE.MAKEFILE_PREFERENCE
788 The ordered list of makefile names
795 .It Va .MAKE.MAKEFILES
796 The list of makefiles read by
798 which is useful for tracking dependencies.
799 Each makefile is recorded only once, regardless of the number of times read.
801 Processed after reading all makefiles.
802 Can affect the mode that
805 It can contain a number of keywords:
806 .Bl -hang -width ignore-cmd
816 into "meta" mode, where meta files are created for each target
817 to capture the command run, the output generated and if
819 is available, the system calls which are of interest to
821 The captured output can be very useful when diagnosing errors.
822 .It Pa curdirOk= Ar bf
825 will not create .meta files in
827 This can be overridden by setting
829 to a value which represents True.
831 For debugging, it can be useful to inlcude the environment
834 If in "meta" mode, print a clue about the target being built.
835 This is useful if the build is otherwise running silently.
836 The message printed the value of:
837 .Va .MAKE.META.PREFIX .
839 Some makefiles have commands which are simply not stable.
840 This keyword causes them to be ignored for
841 determining whether a target is out of date in "meta" mode.
847 is True, when a .meta file is created, mark the target
850 .It Va .MAKE.META.BAILIWICK
851 In "meta" mode, provides a list of prefixes which
852 match the directories controlled by
854 If a file that was generated outside of
856 but within said bailiwick is missing,
857 the current target is considered out-of-date.
858 .It Va .MAKE.META.CREATED
859 In "meta" mode, this variable contains a list of all the meta files
861 If not empty, it can be used to trigger processing of
862 .Va .MAKE.META.FILES .
863 .It Va .MAKE.META.FILES
864 In "meta" mode, this variable contains a list of all the meta files
865 used (updated or not).
866 This list can be used to process the meta files to extract dependency
868 .It Va .MAKE.META.IGNORE_PATHS
869 Provides a list of path prefixes that should be ignored;
870 because the contents are expected to change over time.
871 The default list includes:
872 .Ql Pa /dev /etc /proc /tmp /var/run /var/tmp
873 .It Va .MAKE.META.PREFIX
874 Defines the message printed for each meta file updated in "meta verbose" mode.
875 The default value is:
876 .Dl Building ${.TARGET:H:tA}/${.TARGET:T}
877 .It Va .MAKEOVERRIDES
878 This variable is used to record the names of variables assigned to
879 on the command line, so that they may be exported as part of
881 This behaviour can be disabled by assigning an empty value to
882 .Ql Va .MAKEOVERRIDES
884 Extra variables can be exported from a makefile
885 by appending their names to
886 .Ql Va .MAKEOVERRIDES .
888 is re-exported whenever
889 .Ql Va .MAKEOVERRIDES
891 .It Va .MAKE.PATH_FILEMON
896 support, this is set to the path of the device node.
897 This allows makefiles to test for this support.
902 The parent process-id of
904 .It Va MAKE_PRINT_VAR_ON_ERROR
907 stops due to an error, it prints its name and the value of
909 as well as the value of any variables named in
910 .Ql Va MAKE_PRINT_VAR_ON_ERROR .
912 This variable is simply assigned a newline character as its value.
913 This allows expansions using the
915 modifier to put a newline between
916 iterations of the loop rather than a space.
917 For example, the printing of
918 .Ql Va MAKE_PRINT_VAR_ON_ERROR
919 could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}.
921 A path to the directory where the targets are built.
922 Its value is determined by trying to
924 to the following directories in order and using the first match:
927 .Ev ${MAKEOBJDIRPREFIX}${.CURDIR}
930 .Ql Ev MAKEOBJDIRPREFIX
931 is set in the environment or on the command line.)
937 is set in the environment or on the command line.)
939 .Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE}
941 .Ev ${.CURDIR} Ns Pa /obj
943 .Pa /usr/obj/ Ns Ev ${.CURDIR}
948 Variable expansion is performed on the value before it's used,
949 so expressions such as
950 .Dl ${.CURDIR:S,^/usr/src,/var/obj,}
952 This is especially useful with
956 may be modified in the makefile as a global variable.
965 to that directory before executing any targets.
968 A path to the directory of the current
972 The basename of the current
977 are both set only while the
980 If you want to retain their current values, assign them to a variable
981 using assignment with expansion:
984 A variable that represents the list of directories that
986 will search for files.
987 The search list should be updated using the target
989 rather than the variable.
991 Alternate path to the current directory.
995 to the canonical path given by
997 However, if the environment variable
999 is set and gives a path to the current directory, then
1006 This behaviour is disabled if
1007 .Ql Ev MAKEOBJDIRPREFIX
1010 contains a variable transform.
1012 is set to the value of
1014 for all programs which
1018 The list of targets explicitly specified on the command line, if any.
1022 lists of directories that
1024 will search for files.
1025 The variable is supported for compatibility with old make programs only,
1030 .Ss Variable modifiers
1031 Variable expansion may be modified to select or modify each word of the
1034 is white-space delimited sequence of characters).
1035 The general format of a variable expansion is as follows:
1037 .Dl ${variable[:modifier[:...]]}
1039 Each modifier begins with a colon,
1040 which may be escaped with a backslash
1043 A set of modifiers can be specified via a variable, as follows:
1045 .Dl modifier_variable=modifier[:...]
1046 .Dl ${variable:${modifier_variable}[:...]}
1048 In this case the first modifier in the modifier_variable does not
1049 start with a colon, since that must appear in the referencing
1051 If any of the modifiers in the modifier_variable contain a dollar sign
1053 these must be doubled to avoid early expansion.
1055 The supported modifiers are:
1058 Replaces each word in the variable with its suffix.
1060 Replaces each word in the variable with everything but the last component.
1061 .It Cm \&:M Ns Ar pattern
1062 Select only those words that match
1064 The standard shell wildcard characters
1071 The wildcard characters may be escaped with a backslash
1073 As a consequence of the way values are split into words, matched,
1074 and then joined, a construct like
1076 will normalise the inter-word spacing, removing all leading and
1077 trailing space, and converting multiple consecutive spaces
1080 .It Cm \&:N Ns Ar pattern
1081 This is identical to
1083 but selects all words which do not match
1086 Order every word in variable alphabetically.
1088 reverse order use the
1090 combination of modifiers.
1092 Randomize words in variable.
1093 The results will be different each time you are referring to the
1094 modified variable; use the assignment with expansion
1096 to prevent such behaviour.
1098 .Bd -literal -offset indent
1099 LIST= uno due tre quattro
1100 RANDOM_LIST= ${LIST:Ox}
1101 STATIC_RANDOM_LIST:= ${LIST:Ox}
1104 @echo "${RANDOM_LIST}"
1105 @echo "${RANDOM_LIST}"
1106 @echo "${STATIC_RANDOM_LIST}"
1107 @echo "${STATIC_RANDOM_LIST}"
1109 may produce output similar to:
1110 .Bd -literal -offset indent
1117 Quotes every shell meta-character in the variable, so that it can be passed
1118 safely through recursive invocations of
1121 Replaces each word in the variable with everything but its suffix.
1123 The value is a format string for
1128 Compute a 32bit hash of the value and encode it as hex digits.
1130 The value is a format string for
1135 Attempt to convert variable to an absolute path using
1137 if that fails, the value is unchanged.
1139 Converts variable to lower-case letters.
1140 .It Cm \&:ts Ns Ar c
1141 Words in the variable are normally separated by a space on expansion.
1142 This modifier sets the separator to the character
1146 is omitted, then no separator is used.
1147 The common escapes (including octal numeric codes), work as expected.
1149 Converts variable to upper-case letters.
1151 Causes the value to be treated as a single word
1152 (possibly containing embedded white space).
1156 Causes the value to be treated as a sequence of
1157 words delimited by white space.
1161 .It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW
1163 Modify the first occurrence of
1165 in the variable's value, replacing it with
1169 is appended to the last slash of the pattern, all occurrences
1170 in each word are replaced.
1173 is appended to the last slash of the pattern, only the first word
1177 is appended to the last slash of the pattern,
1178 then the value is treated as a single word
1179 (possibly containing embedded white space).
1185 is anchored at the beginning of each word.
1188 ends with a dollar sign
1190 it is anchored at the end of each word.
1201 Any character may be used as a delimiter for the parts of the modifier
1203 The anchoring, ampersand and delimiter characters may be escaped with a
1207 Variable expansion occurs in the normal fashion inside both
1211 with the single exception that a backslash is used to prevent the expansion
1214 not a preceding dollar sign as is usual.
1216 .It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW
1220 modifier is just like the
1222 modifier except that the old and new strings, instead of being
1223 simple strings, are an extended regular expression (see
1231 Normally, the first occurrence of the pattern
1233 in each word of the value is substituted with
1237 modifier causes the substitution to apply to at most one word; the
1239 modifier causes the substitution to apply to as many instances of the
1242 as occur in the word or words it is found in; the
1244 modifier causes the value to be treated as a single word
1245 (possibly containing embedded white space).
1250 are orthogonal; the former specifies whether multiple words are
1251 potentially affected, the latter whether multiple substitutions can
1252 potentially occur within each affected word.
1260 are subjected to variable expansion before being parsed as
1261 regular expressions.
1263 Replaces each word in the variable with its last component.
1265 Remove adjacent duplicate words (like
1268 .It Cm \&:\&? Ar true_string Cm \&: Ar false_string
1270 If the variable name (not its value), when parsed as a .if conditional
1271 expression, evaluates to true, return as its value the
1273 otherwise return the
1275 Since the variable name is used as the expression, \&:\&? must be the
1276 first modifier after the variable name itself - which will, of course,
1277 usually contain variable expansions.
1278 A common error is trying to use expressions like
1279 .Dl ${NUMBERS:M42:?match:no}
1280 which actually tests defined(NUMBERS),
1281 to determine is any words match "42" you need to use something like:
1282 .Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} .
1283 .It Ar :old_string=new_string
1286 style variable substitution.
1287 It must be the last modifier specified.
1292 do not contain the pattern matching character
1294 then it is assumed that they are
1295 anchored at the end of each word, so only suffixes or entire
1296 words may be replaced.
1304 Variable expansion occurs in the normal fashion inside both
1308 with the single exception that a backslash is used to prevent the
1309 expansion of a dollar sign
1311 not a preceding dollar sign as is usual.
1313 .It Cm \&:@ Ar temp Cm @ Ar string Cm @
1315 This is the loop expansion mechanism from the OSF Development
1316 Environment (ODE) make.
1319 loops expansion occurs at the time of
1323 to each word in the variable and evaluate
1325 The ODE convention is that
1327 should start and end with a period.
1329 .Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
1331 However a single character variable is often more readable:
1332 .Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
1333 .It Cm \&:U Ns Ar newval
1334 If the variable is undefined
1337 If the variable is defined, the existing value is returned.
1338 This is another ODE make feature.
1339 It is handy for setting per-target CFLAGS for instance:
1340 .Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
1341 If a value is only required if the variable is undefined, use:
1342 .Dl ${VAR:D:Unewval}
1343 .It Cm \&:D Ns Ar newval
1344 If the variable is defined
1348 The name of the variable is the value.
1350 The path of the node which has the same name as the variable
1352 If no such node exists or its path is null, then the
1353 name of the variable is used.
1354 In order for this modifier to work, the name (node) must at least have
1355 appeared on the rhs of a dependency.
1357 .It Cm \&:\&! Ar cmd Cm \&!
1359 The output of running
1363 If the variable is non-empty it is run as a command and the output
1364 becomes the new value.
1365 .It Cm \&::= Ns Ar str
1366 The variable is assigned the value
1369 This modifier and its variations are useful in
1370 obscure situations such as wanting to set a variable when shell commands
1372 These assignment modifiers always expand to
1373 nothing, so if appearing in a rule line by themselves should be
1374 preceded with something to keep
1380 helps avoid false matches with the
1384 modifier and since substitution always occurs the
1386 form is vaguely appropriate.
1387 .It Cm \&::?= Ns Ar str
1390 but only if the variable does not already have a value.
1391 .It Cm \&::+= Ns Ar str
1395 .It Cm \&::!= Ns Ar cmd
1396 Assign the output of
1399 .It Cm \&:\&[ Ns Ar range Ns Cm \&]
1400 Selects one or more words from the value,
1401 or performs other operations related to the way in which the
1402 value is divided into words.
1404 Ordinarily, a value is treated as a sequence of words
1405 delimited by white space.
1406 Some modifiers suppress this behaviour,
1407 causing a value to be treated as a single word
1408 (possibly containing embedded white space).
1409 An empty value, or a value that consists entirely of white-space,
1410 is treated as a single word.
1411 For the purposes of the
1413 modifier, the words are indexed both forwards using positive integers
1414 (where index 1 represents the first word),
1415 and backwards using negative integers
1416 (where index \-1 represents the last word).
1420 is subjected to variable expansion, and the expanded result is
1421 then interpreted as follows:
1422 .Bl -tag -width index
1425 Selects a single word from the value.
1427 .It Ar start Ns Cm \&.. Ns Ar end
1428 Selects all words from
1435 selects all words from the second word to the last word.
1440 then the words are output in reverse order.
1443 selects all the words from last to first.
1446 Causes subsequent modifiers to treat the value as a single word
1447 (possibly containing embedded white space).
1448 Analogous to the effect of
1457 Causes subsequent modifiers to treat the value as a sequence of words
1458 delimited by white space.
1459 Analogous to the effect of
1464 Returns the number of words in the value.
1467 .Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
1468 Makefile inclusion, conditional structures and for loops reminiscent
1469 of the C programming language are provided in
1471 All such structures are identified by a line beginning with a single
1475 Files are included with either
1476 .Cm \&.include Aq Ar file
1478 .Cm \&.include Pf \*q Ar file Ns \*q .
1479 Variables between the angle brackets or double quotes are expanded
1480 to form the file name.
1481 If angle brackets are used, the included makefile is expected to be in
1482 the system makefile directory.
1483 If double quotes are used, the including makefile's directory and any
1484 directories specified using the
1486 option are searched before the system
1488 For compatibility with other versions of
1490 .Ql include file ...
1492 If the include statement is written as
1496 then errors locating and/or opening include files are ignored.
1498 Conditional expressions are also preceded by a single dot as the first
1499 character of a line.
1500 The possible conditionals are as follows:
1502 .It Ic .error Ar message
1503 The message is printed along with the name of the makefile and line number,
1507 .It Ic .export Ar variable ...
1508 Export the specified global variable.
1509 If no variable list is provided, all globals are exported
1510 except for internal variables (those that start with
1512 This is not affected by the
1514 flag, so should be used with caution.
1515 For compatibility with other
1518 .Ql export variable=value
1521 Appending a variable name to
1523 is equivalent to exporting a variable.
1524 .It Ic .export-env Ar variable ...
1527 except that the variable is not appended to
1528 .Va .MAKE.EXPORTED .
1529 This allows exporting a value to the environment which is different from that
1533 .It Ic .info Ar message
1534 The message is printed along with the name of the makefile and line number.
1535 .It Ic .undef Ar variable
1536 Un-define the specified global variable.
1537 Only global variables may be un-defined.
1538 .It Ic .unexport Ar variable ...
1541 The specified global
1543 will be removed from
1544 .Va .MAKE.EXPORTED .
1545 If no variable list is provided, all globals are unexported,
1549 .It Ic .unexport-env
1550 Unexport all globals previously exported and
1551 clear the environment inherited from the parent.
1552 This operation will cause a memory leak of the original environment,
1553 so should be used sparingly.
1556 being 0, would make sense.
1557 Also note that any variables which originated in the parent environment
1558 should be explicitly preserved if desired.
1560 .Bd -literal -offset indent
1561 .Li .if ${.MAKE.LEVEL} == 0
1568 Would result in an environment containing only
1570 which is the minimal useful environment.
1573 will also be pushed into the new environment.
1574 .It Ic .warning Ar message
1575 The message prefixed by
1577 is printed along with the name of the makefile and line number.
1578 .It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ...
1579 Test the value of an expression.
1580 .It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1581 Test the value of a variable.
1582 .It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1583 Test the value of a variable.
1584 .It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1585 Test the target being built.
1586 .It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ...
1587 Test the target being built.
1589 Reverse the sense of the last conditional.
1590 .It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ...
1595 .It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1600 .It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1605 .It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1610 .It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1616 End the body of the conditional.
1621 may be any one of the following:
1622 .Bl -tag -width "Cm XX"
1625 .It Cm \&\*[Am]\*[Am]
1628 of higher precedence than
1634 will only evaluate a conditional as far as is necessary to determine
1636 Parentheses may be used to change the order of evaluation.
1637 The boolean operator
1639 may be used to logically negate an entire
1641 It is of higher precedence than
1642 .Ql Ic \&\*[Am]\*[Am] .
1646 may be any of the following:
1647 .Bl -tag -width defined
1649 Takes a variable name as an argument and evaluates to true if the variable
1652 Takes a target name as an argument and evaluates to true if the target
1653 was specified as part of
1655 command line or was declared the default target (either implicitly or
1658 before the line containing the conditional.
1660 Takes a variable, with possible modifiers, and evaluates to true if
1661 the expansion of the variable would result in an empty string.
1663 Takes a file name as an argument and evaluates to true if the file exists.
1664 The file is searched for on the system search path (see
1667 Takes a target name as an argument and evaluates to true if the target
1670 Takes a target name as an argument and evaluates to true if the target
1671 has been defined and has commands associated with it.
1675 may also be an arithmetic or string comparison.
1676 Variable expansion is
1677 performed on both sides of the comparison, after which the integral
1678 values are compared.
1679 A value is interpreted as hexadecimal if it is
1680 preceded by 0x, otherwise it is decimal; octal numbers are not supported.
1681 The standard C relational operators are all supported.
1683 variable expansion, either the left or right hand side of a
1687 operator is not an integral value, then
1688 string comparison is performed between the expanded
1690 If no relational operator is given, it is assumed that the expanded
1691 variable is being compared against 0 or an empty string in the case
1692 of a string comparison.
1696 is evaluating one of these conditional expressions, and it encounters
1697 a (white-space separated) word it doesn't recognize, either the
1701 expression is applied to it, depending on the form of the conditional.
1709 expression is applied.
1710 Similarly, if the form is
1713 .Ql Ic .ifnmake , the
1715 expression is applied.
1717 If the conditional evaluates to true the parsing of the makefile continues
1719 If it evaluates to false, the following lines are skipped.
1720 In both cases this continues until a
1726 For loops are typically used to apply a set of rules to a list of files.
1727 The syntax of a for loop is:
1729 .Bl -tag -compact -width Ds
1730 .It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression
1737 is evaluated, it is split into words.
1738 On each iteration of the loop, one word is taken and assigned to each
1742 are substituted into the
1744 inside the body of the for loop.
1745 The number of words must come out even; that is, if there are three
1746 iteration variables, the number of words provided must be a multiple
1749 Comments begin with a hash
1751 character, anywhere but in a shell
1752 command line, and continue to the end of an unescaped new line.
1753 .Sh SPECIAL SOURCES (ATTRIBUTES)
1754 .Bl -tag -width .IGNOREx
1756 Target is never out of date, but always execute commands anyway.
1758 Ignore any errors from the commands associated with this target, exactly
1759 as if they all were preceded by a dash
1761 .\" .It Ic .INVISIBLE
1766 Mark all sources of this target as being up-to-date.
1768 Execute the commands associated with this target even if the
1772 options were specified.
1773 Normally used to mark recursive
1776 Create a meta file for the target, even if it is flagged as
1781 Usage in conjunction with
1783 is the most likely case.
1784 In "meta" mode, the target is out-of-date if the meta file is missing.
1786 Do not create a meta file for the target.
1787 Meta files are also not created for
1794 Ignore differences in commands when deciding if target is out of date.
1795 This is useful if the command contains a value which always changes.
1796 If the number of commands change, though, the target will still be out of date.
1797 The same effect applies to any command line that uses the variable
1799 which can be used for that purpose even when not otherwise needed or desired:
1800 .Bd -literal -offset indent
1802 skip-compare-for-some:
1803 @echo this will be compared
1804 @echo this will not ${.OODATE:M.NOMETA_CMP}
1805 @echo this will also be compared
1810 pattern suppresses any expansion of the unwanted variable.
1812 Do not search for the target in the directories specified by
1817 selects the first target it encounters as the default target to be built
1818 if no target was specified.
1819 This source prevents this target from being selected.
1821 If a target is marked with this attribute and
1823 can't figure out how to create it, it will ignore this fact and assume
1824 the file isn't needed or already exists.
1827 correspond to an actual file; it is always considered to be out of date,
1828 and will not be created with the
1831 Suffix-transformation rules are not applied to
1837 is interrupted, it normally removes any partially made targets.
1838 This source prevents the target from being removed.
1843 Do not echo any of the commands associated with this target, exactly
1844 as if they all were preceded by an at sign
1847 Turn the target into
1850 When the target is used as a source for another target, the other target
1851 acquires the commands, sources, and attributes (except for
1855 If the target already has commands, the
1857 target's commands are appended
1864 target commands to the target.
1868 appears in a dependency line, the sources that precede it are
1869 made before the sources that succeed it in the line.
1870 Since the dependents of files are not made until the file itself
1871 could be made, this also stops the dependents being built unless they
1872 are needed for another branch of the dependency tree.
1885 the output is always
1891 The ordering imposed by
1893 is only relevant for parallel makes.
1896 Special targets may not be included with other targets, i.e. they must be
1897 the only target specified.
1898 .Bl -tag -width .BEGINx
1900 Any command lines attached to this target are executed before anything
1905 rule for any target (that was used only as a
1908 can't figure out any other way to create.
1909 Only the shell script is used.
1912 variable of a target that inherits
1915 to the target's own name.
1917 Any command lines attached to this target are executed after everything
1920 Any command lines attached to this target are executed when another target fails.
1923 variable is set to the target that failed.
1925 .Ic MAKE_PRINT_VAR_ON_ERROR .
1927 Mark each of the sources with the
1930 If no sources are specified, this is the equivalent of specifying the
1936 is interrupted, the commands for this target will be executed.
1938 If no target is specified when
1940 is invoked, this target will be built.
1942 This target provides a way to specify flags for
1944 when the makefile is used.
1945 The flags are as if typed to the shell, though the
1949 .\" XXX: NOT YET!!!!
1950 .\" .It Ic .NOTPARALLEL
1951 .\" The named targets are executed in non parallel mode.
1952 .\" If no targets are
1953 .\" specified, then all targets are executed in non parallel mode.
1957 attribute to any specified sources.
1959 Disable parallel mode.
1963 for compatibility with other pmake variants.
1965 The named targets are made in sequence.
1966 This ordering does not add targets to the list of targets to be made.
1967 Since the dependents of a target do not get built until the target itself
1968 could be built, unless
1970 is built by another part of the dependency graph,
1971 the following is a dependency loop:
1977 The ordering imposed by
1979 is only relevant for parallel makes.
1980 .\" XXX: NOT YET!!!!
1981 .\" .It Ic .PARALLEL
1982 .\" The named targets are executed in parallel mode.
1983 .\" If no targets are
1984 .\" specified, then all targets are executed in parallel mode.
1986 The sources are directories which are to be searched for files not
1987 found in the current directory.
1988 If no sources are specified, any previously specified directories are
1990 If the source is the special
1992 target, then the current working
1993 directory is searched last.
1994 .It Ic .PATH. Ns Va suffix
1997 but applies only to files with a particular suffix.
1998 The suffix must have been previously declared with
2003 attribute to any specified sources.
2007 attribute to any specified sources.
2008 If no sources are specified, the
2010 attribute is applied to every
2015 will use to execute commands.
2016 The sources are a set of
2019 .Bl -tag -width hasErrCtls
2021 This is the minimal specification, used to select one of the builtin
2028 Specifies the path to the shell.
2030 Indicates whether the shell supports exit on error.
2032 The command to turn on error checking.
2034 The command to disable error checking.
2036 The command to turn on echoing of commands executed.
2038 The command to turn off echoing of commands executed.
2040 The output to filter after issuing the
2043 It is typically identical to
2046 The flag to pass the shell to enable error checking.
2048 The flag to pass the shell to enable command echoing.
2050 The string literal to pass the shell that results in a single newline
2051 character when used outside of any quoting characters.
2055 \&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e
2056 check="set \-e" ignore="set +e" \e
2057 echo="set \-v" quiet="set +v" filter="set +v" \e
2058 echoFlag=v errFlag=e newline="'\en'"
2063 attribute to any specified sources.
2064 If no sources are specified, the
2066 attribute is applied to every
2067 command in the file.
2069 This target gets run when a dependency file contains stale entries, having
2071 set to the name of that dependency file.
2073 Each source specifies a suffix to
2075 If no sources are specified, any previously specified suffixes are deleted.
2076 It allows the creation of suffix-transformation rules.
2082 cc \-o ${.TARGET} \-c ${.IMPSRC}
2087 uses the following environment variables, if they exist:
2093 .Ev MAKEOBJDIRPREFIX ,
2099 .Ev MAKEOBJDIRPREFIX
2102 may only be set in the environment or on the command line to
2104 and not as makefile variables;
2105 see the description of
2109 .Bl -tag -width /usr/share/mk -compact
2111 list of dependencies
2113 list of dependencies
2115 list of dependencies
2119 system makefile directory
2122 The basic make syntax is compatible between different versions of make,
2123 however the special variables, variable modifiers and conditionals are not.
2125 The way that parallel makes are scheduled changed in
2127 so that .ORDER and .WAIT apply recursively to the dependent nodes.
2128 The algorithms used may change again in the future.
2130 The way that .for loop variables are substituted changed after
2132 so that they still appear to be variable expansions.
2133 In particular this stops them being treated as syntax, and removes some
2134 obscure problems using them in .if statements.
2139 is derived from NetBSD
2141 It uses autoconf to facilitate portability to other platforms.
2149 implementation is based on Adam De Boor's pmake program which was written
2150 for Sprite at Berkeley.
2151 It was designed to be a parallel distributed make running jobs on different
2152 machines using a daemon called
2155 Historically the target/dependency
2157 has been used to FoRCe rebuilding (since the target/dependency
2158 does not exist... unless someone creates an
2164 syntax is difficult to parse without actually acting of the data.
2165 For instance finding the end of a variable use should involve scanning each
2166 the modifiers using the correct terminator for each field.
2169 just counts {} and () in order to find the end of a variable expansion.
2171 There is no way of escaping a space character in a filename.