xref: /freebsd/contrib/bmake/make.1 (revision 49caa483b3fafffd9cf5197eb30e8bb235aa7410)
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30.\"	from: @(#)make.1	8.4 (Berkeley) 3/19/94
31.\"
32.Dd April 27, 2020
33.Dt MAKE 1
34.Os
35.Sh NAME
36.Nm make
37.Nd maintain program dependencies
38.Sh SYNOPSIS
39.Nm
40.Op Fl BeikNnqrstWwX
41.Op Fl C Ar directory
42.Op Fl D Ar variable
43.Op Fl d Ar flags
44.Op Fl f Ar makefile
45.Op Fl I Ar directory
46.Op Fl J Ar private
47.Op Fl j Ar max_jobs
48.Op Fl m Ar directory
49.Op Fl T Ar file
50.Op Fl V Ar variable
51.Op Fl v Ar variable
52.Op Ar variable=value
53.Op Ar target ...
54.Sh DESCRIPTION
55.Nm
56is a program designed to simplify the maintenance of other programs.
57Its input is a list of specifications as to the files upon which programs
58and other files depend.
59If no
60.Fl f Ar makefile
61makefile option is given,
62.Nm
63will try to open
64.Ql Pa makefile
65then
66.Ql Pa Makefile
67in order to find the specifications.
68If the file
69.Ql Pa .depend
70exists, it is read (see
71.Xr mkdep 1 ) .
72.Pp
73This manual page is intended as a reference document only.
74For a more thorough description of
75.Nm
76and makefiles, please refer to
77.%T "PMake \- A Tutorial" .
78.Pp
79.Nm
80will prepend the contents of the
81.Va MAKEFLAGS
82environment variable to the command line arguments before parsing them.
83.Pp
84The options are as follows:
85.Bl -tag -width Ds
86.It Fl B
87Try to be backwards compatible by executing a single shell per command and
88by executing the commands to make the sources of a dependency line in sequence.
89.It Fl C Ar directory
90Change to
91.Ar directory
92before reading the makefiles or doing anything else.
93If multiple
94.Fl C
95options are specified, each is interpreted relative to the previous one:
96.Fl C Pa / Fl C Pa etc
97is equivalent to
98.Fl C Pa /etc .
99.It Fl D Ar variable
100Define
101.Ar variable
102to be 1, in the global context.
103.It Fl d Ar [-]flags
104Turn on debugging, and specify which portions of
105.Nm
106are to print debugging information.
107Unless the flags are preceded by
108.Ql \-
109they are added to the
110.Va MAKEFLAGS
111environment variable and will be processed by any child make processes.
112By default, debugging information is printed to standard error,
113but this can be changed using the
114.Ar F
115debugging flag.
116The debugging output is always unbuffered; in addition, if debugging
117is enabled but debugging output is not directed to standard output,
118then the standard output is line buffered.
119.Ar Flags
120is one or more of the following:
121.Bl -tag -width Ds
122.It Ar A
123Print all possible debugging information;
124equivalent to specifying all of the debugging flags.
125.It Ar a
126Print debugging information about archive searching and caching.
127.It Ar C
128Print debugging information about current working directory.
129.It Ar c
130Print debugging information about conditional evaluation.
131.It Ar d
132Print debugging information about directory searching and caching.
133.It Ar e
134Print debugging information about failed commands and targets.
135.It Ar F Ns Oo Sy \&+ Oc Ns Ar filename
136Specify where debugging output is written.
137This must be the last flag, because it consumes the remainder of
138the argument.
139If the character immediately after the
140.Ql F
141flag is
142.Ql \&+ ,
143then the file will be opened in append mode;
144otherwise the file will be overwritten.
145If the file name is
146.Ql stdout
147or
148.Ql stderr
149then debugging output will be written to the
150standard output or standard error output file descriptors respectively
151(and the
152.Ql \&+
153option has no effect).
154Otherwise, the output will be written to the named file.
155If the file name ends
156.Ql .%d
157then the
158.Ql %d
159is replaced by the pid.
160.It Ar f
161Print debugging information about loop evaluation.
162.It Ar "g1"
163Print the input graph before making anything.
164.It Ar "g2"
165Print the input graph after making everything, or before exiting
166on error.
167.It Ar "g3"
168Print the input graph before exiting on error.
169.It Ar j
170Print debugging information about running multiple shells.
171.It Ar l
172Print commands in Makefiles regardless of whether or not they are prefixed by
173.Ql @
174or other "quiet" flags.
175Also known as "loud" behavior.
176.It Ar M
177Print debugging information about "meta" mode decisions about targets.
178.It Ar m
179Print debugging information about making targets, including modification
180dates.
181.It Ar n
182Don't delete the temporary command scripts created when running commands.
183These temporary scripts are created in the directory
184referred to by the
185.Ev TMPDIR
186environment variable, or in
187.Pa /tmp
188if
189.Ev TMPDIR
190is unset or set to the empty string.
191The temporary scripts are created by
192.Xr mkstemp 3 ,
193and have names of the form
194.Pa makeXXXXXX .
195.Em NOTE :
196This can create many files in
197.Ev TMPDIR
198or
199.Pa /tmp ,
200so use with care.
201.It Ar p
202Print debugging information about makefile parsing.
203.It Ar s
204Print debugging information about suffix-transformation rules.
205.It Ar t
206Print debugging information about target list maintenance.
207.It Ar V
208Force the
209.Fl V
210option to print raw values of variables, overriding the default behavior
211set via
212.Va .MAKE.EXPAND_VARIABLES .
213.It Ar v
214Print debugging information about variable assignment.
215.It Ar x
216Run shell commands with
217.Fl x
218so the actual commands are printed as they are executed.
219.El
220.It Fl e
221Specify that environment variables override macro assignments within
222makefiles.
223.It Fl f Ar makefile
224Specify a makefile to read instead of the default
225.Ql Pa makefile .
226If
227.Ar makefile
228is
229.Ql Fl ,
230standard input is read.
231Multiple makefiles may be specified, and are read in the order specified.
232.It Fl I Ar directory
233Specify a directory in which to search for makefiles and included makefiles.
234The system makefile directory (or directories, see the
235.Fl m
236option) is automatically included as part of this list.
237.It Fl i
238Ignore non-zero exit of shell commands in the makefile.
239Equivalent to specifying
240.Ql Fl
241before each command line in the makefile.
242.It Fl J Ar private
243This option should
244.Em not
245be specified by the user.
246.Pp
247When the
248.Ar j
249option is in use in a recursive build, this option is passed by a make
250to child makes to allow all the make processes in the build to
251cooperate to avoid overloading the system.
252.It Fl j Ar max_jobs
253Specify the maximum number of jobs that
254.Nm
255may have running at any one time.
256The value is saved in
257.Va .MAKE.JOBS .
258Turns compatibility mode off, unless the
259.Ar B
260flag is also specified.
261When compatibility mode is off, all commands associated with a
262target are executed in a single shell invocation as opposed to the
263traditional one shell invocation per line.
264This can break traditional scripts which change directories on each
265command invocation and then expect to start with a fresh environment
266on the next line.
267It is more efficient to correct the scripts rather than turn backwards
268compatibility on.
269.It Fl k
270Continue processing after errors are encountered, but only on those targets
271that do not depend on the target whose creation caused the error.
272.It Fl m Ar directory
273Specify a directory in which to search for sys.mk and makefiles included
274via the
275.Li \&< Ns Ar file Ns Li \&> Ns -style
276include statement.
277The
278.Fl m
279option can be used multiple times to form a search path.
280This path will override the default system include path: /usr/share/mk.
281Furthermore the system include path will be appended to the search path used
282for
283.Li \*q Ns Ar file Ns Li \*q Ns -style
284include statements (see the
285.Fl I
286option).
287.Pp
288If a file or directory name in the
289.Fl m
290argument (or the
291.Ev MAKESYSPATH
292environment variable) starts with the string
293.Qq \&.../
294then
295.Nm
296will search for the specified file or directory named in the remaining part
297of the argument string.
298The search starts with the current directory of
299the Makefile and then works upward towards the root of the file system.
300If the search is successful, then the resulting directory replaces the
301.Qq \&.../
302specification in the
303.Fl m
304argument.
305If used, this feature allows
306.Nm
307to easily search in the current source tree for customized sys.mk files
308(e.g., by using
309.Qq \&.../mk/sys.mk
310as an argument).
311.It Fl n
312Display the commands that would have been executed, but do not
313actually execute them unless the target depends on the .MAKE special
314source (see below).
315.It Fl N
316Display the commands which would have been executed, but do not
317actually execute any of them; useful for debugging top-level makefiles
318without descending into subdirectories.
319.It Fl q
320Do not execute any commands, but exit 0 if the specified targets are
321up-to-date and 1, otherwise.
322.It Fl r
323Do not use the built-in rules specified in the system makefile.
324.It Fl s
325Do not echo any commands as they are executed.
326Equivalent to specifying
327.Ql Ic @
328before each command line in the makefile.
329.It Fl T Ar tracefile
330When used with the
331.Fl j
332flag,
333append a trace record to
334.Ar tracefile
335for each job started and completed.
336.It Fl t
337Rather than re-building a target as specified in the makefile, create it
338or update its modification time to make it appear up-to-date.
339.It Fl V Ar variable
340Print the value of
341.Ar variable .
342Do not build any targets.
343Multiple instances of this option may be specified;
344the variables will be printed one per line,
345with a blank line for each null or undefined variable.
346The value printed is extracted from the global context after all
347makefiles have been read.
348By default, the raw variable contents (which may
349include additional unexpanded variable references) are shown.
350If
351.Ar variable
352contains a
353.Ql \&$
354then the value will be recursively expanded to its complete resultant
355text before printing.
356The expanded value will also be printed if
357.Va .MAKE.EXPAND_VARIABLES
358is set to true and
359the
360.Fl dV
361option has not been used to override it.
362Note that loop-local and target-local variables, as well as values
363taken temporarily by global variables during makefile processing, are
364not accessible via this option.
365The
366.Fl dv
367debug mode can be used to see these at the cost of generating
368substantial extraneous output.
369.It Fl v Ar variable
370Like
371.Fl V
372but the variable is always expanded to its complete value.
373.It Fl W
374Treat any warnings during makefile parsing as errors.
375.It Fl w
376Print entering and leaving directory messages, pre and post processing.
377.It Fl X
378Don't export variables passed on the command line to the environment
379individually.
380Variables passed on the command line are still exported
381via the
382.Va MAKEFLAGS
383environment variable.
384This option may be useful on systems which have a small limit on the
385size of command arguments.
386.It Ar variable=value
387Set the value of the variable
388.Ar variable
389to
390.Ar value .
391Normally, all values passed on the command line are also exported to
392sub-makes in the environment.
393The
394.Fl X
395flag disables this behavior.
396Variable assignments should follow options for POSIX compatibility
397but no ordering is enforced.
398.El
399.Pp
400There are seven different types of lines in a makefile: file dependency
401specifications, shell commands, variable assignments, include statements,
402conditional directives, for loops, and comments.
403.Pp
404In general, lines may be continued from one line to the next by ending
405them with a backslash
406.Pq Ql \e .
407The trailing newline character and initial whitespace on the following
408line are compressed into a single space.
409.Sh FILE DEPENDENCY SPECIFICATIONS
410Dependency lines consist of one or more targets, an operator, and zero
411or more sources.
412This creates a relationship where the targets
413.Dq depend
414on the sources
415and are usually created from them.
416The exact relationship between the target and the source is determined
417by the operator that separates them.
418The three operators are as follows:
419.Bl -tag -width flag
420.It Ic \&:
421A target is considered out-of-date if its modification time is less than
422those of any of its sources.
423Sources for a target accumulate over dependency lines when this operator
424is used.
425The target is removed if
426.Nm
427is interrupted.
428.It Ic \&!
429Targets are always re-created, but not until all sources have been
430examined and re-created as necessary.
431Sources for a target accumulate over dependency lines when this operator
432is used.
433The target is removed if
434.Nm
435is interrupted.
436.It Ic \&::
437If no sources are specified, the target is always re-created.
438Otherwise, a target is considered out-of-date if any of its sources has
439been modified more recently than the target.
440Sources for a target do not accumulate over dependency lines when this
441operator is used.
442The target will not be removed if
443.Nm
444is interrupted.
445.El
446.Pp
447Targets and sources may contain the shell wildcard values
448.Ql \&? ,
449.Ql * ,
450.Ql [] ,
451and
452.Ql {} .
453The values
454.Ql \&? ,
455.Ql * ,
456and
457.Ql []
458may only be used as part of the final
459component of the target or source, and must be used to describe existing
460files.
461The value
462.Ql {}
463need not necessarily be used to describe existing files.
464Expansion is in directory order, not alphabetically as done in the shell.
465.Sh SHELL COMMANDS
466Each target may have associated with it one or more lines of shell
467commands, normally
468used to create the target.
469Each of the lines in this script
470.Em must
471be preceded by a tab.
472(For historical reasons, spaces are not accepted.)
473While targets can appear in many dependency lines if desired, by
474default only one of these rules may be followed by a creation
475script.
476If the
477.Ql Ic \&::
478operator is used, however, all rules may include scripts and the
479scripts are executed in the order found.
480.Pp
481Each line is treated as a separate shell command, unless the end of
482line is escaped with a backslash
483.Pq Ql \e
484in which case that line and the next are combined.
485.\" The escaped newline is retained and passed to the shell, which
486.\" normally ignores it.
487.\" However, the tab at the beginning of the following line is removed.
488If the first characters of the command are any combination of
489.Ql Ic @ ,
490.Ql Ic + ,
491or
492.Ql Ic \- ,
493the command is treated specially.
494A
495.Ql Ic @
496causes the command not to be echoed before it is executed.
497A
498.Ql Ic +
499causes the command to be executed even when
500.Fl n
501is given.
502This is similar to the effect of the .MAKE special source,
503except that the effect can be limited to a single line of a script.
504A
505.Ql Ic \-
506in compatibility mode
507causes any non-zero exit status of the command line to be ignored.
508.Pp
509When
510.Nm
511is run in jobs mode with
512.Fl j Ar max_jobs ,
513the entire script for the target is fed to a
514single instance of the shell.
515In compatibility (non-jobs) mode, each command is run in a separate process.
516If the command contains any shell meta characters
517.Pq Ql #=|^(){};&<>*?[]:$`\e\en
518it will be passed to the shell; otherwise
519.Nm
520will attempt direct execution.
521If a line starts with
522.Ql Ic \-
523and the shell has ErrCtl enabled then failure of the command line
524will be ignored as in compatibility mode.
525Otherwise
526.Ql Ic \-
527affects the entire job;
528the script will stop at the first command line that fails,
529but the target will not be deemed to have failed.
530.Pp
531Makefiles should be written so that the mode of
532.Nm
533operation does not change their behavior.
534For example, any command which needs to use
535.Dq cd
536or
537.Dq chdir
538without potentially changing the directory for subsequent commands
539should be put in parentheses so it executes in a subshell.
540To force the use of one shell, escape the line breaks so as to make
541the whole script one command.
542For example:
543.Bd -literal -offset indent
544avoid-chdir-side-effects:
545	@echo Building $@ in `pwd`
546	@(cd ${.CURDIR} && ${MAKE} $@)
547	@echo Back in `pwd`
548
549ensure-one-shell-regardless-of-mode:
550	@echo Building $@ in `pwd`; \e
551	(cd ${.CURDIR} && ${MAKE} $@); \e
552	echo Back in `pwd`
553.Ed
554.Pp
555Since
556.Nm
557will
558.Xr chdir 2
559to
560.Ql Va .OBJDIR
561before executing any targets, each child process
562starts with that as its current working directory.
563.Sh VARIABLE ASSIGNMENTS
564Variables in make are much like variables in the shell, and, by tradition,
565consist of all upper-case letters.
566.Ss Variable assignment modifiers
567The five operators that can be used to assign values to variables are as
568follows:
569.Bl -tag -width Ds
570.It Ic \&=
571Assign the value to the variable.
572Any previous value is overridden.
573.It Ic \&+=
574Append the value to the current value of the variable.
575.It Ic \&?=
576Assign the value to the variable if it is not already defined.
577.It Ic \&:=
578Assign with expansion, i.e. expand the value before assigning it
579to the variable.
580Normally, expansion is not done until the variable is referenced.
581.Em NOTE :
582References to undefined variables are
583.Em not
584expanded.
585This can cause problems when variable modifiers are used.
586.It Ic \&!=
587Expand the value and pass it to the shell for execution and assign
588the result to the variable.
589Any newlines in the result are replaced with spaces.
590.El
591.Pp
592Any white-space before the assigned
593.Ar value
594is removed; if the value is being appended, a single space is inserted
595between the previous contents of the variable and the appended value.
596.Pp
597Variables are expanded by surrounding the variable name with either
598curly braces
599.Pq Ql {}
600or parentheses
601.Pq Ql ()
602and preceding it with
603a dollar sign
604.Pq Ql \&$ .
605If the variable name contains only a single letter, the surrounding
606braces or parentheses are not required.
607This shorter form is not recommended.
608.Pp
609If the variable name contains a dollar, then the name itself is expanded first.
610This allows almost arbitrary variable names, however names containing dollar,
611braces, parenthesis, or whitespace are really best avoided!
612.Pp
613If the result of expanding a variable contains a dollar sign
614.Pq Ql \&$
615the string is expanded again.
616.Pp
617Variable substitution occurs at three distinct times, depending on where
618the variable is being used.
619.Bl -enum
620.It
621Variables in dependency lines are expanded as the line is read.
622.It
623Variables in shell commands are expanded when the shell command is
624executed.
625.It
626.Dq .for
627loop index variables are expanded on each loop iteration.
628Note that other variables are not expanded inside loops so
629the following example code:
630.Bd -literal -offset indent
631
632.Dv .for i in 1 2 3
633a+=     ${i}
634j=      ${i}
635b+=     ${j}
636.Dv .endfor
637
638all:
639	@echo ${a}
640	@echo ${b}
641
642.Ed
643will print:
644.Bd -literal -offset indent
6451 2 3
6463 3 3
647
648.Ed
649Because while ${a} contains
650.Dq 1 2 3
651after the loop is executed, ${b}
652contains
653.Dq ${j} ${j} ${j}
654which expands to
655.Dq 3 3 3
656since after the loop completes ${j} contains
657.Dq 3 .
658.El
659.Ss Variable classes
660The four different classes of variables (in order of increasing precedence)
661are:
662.Bl -tag -width Ds
663.It Environment variables
664Variables defined as part of
665.Nm Ns 's
666environment.
667.It Global variables
668Variables defined in the makefile or in included makefiles.
669.It Command line variables
670Variables defined as part of the command line.
671.It Local variables
672Variables that are defined specific to a certain target.
673.El
674.Pp
675Local variables are all built in and their values vary magically from
676target to target.
677It is not currently possible to define new local variables.
678The seven local variables are as follows:
679.Bl -tag -width ".ARCHIVE" -offset indent
680.It Va .ALLSRC
681The list of all sources for this target; also known as
682.Ql Va \&> .
683.It Va .ARCHIVE
684The name of the archive file; also known as
685.Ql Va \&! .
686.It Va .IMPSRC
687In suffix-transformation rules, the name/path of the source from which the
688target is to be transformed (the
689.Dq implied
690source); also known as
691.Ql Va \&< .
692It is not defined in explicit rules.
693.It Va .MEMBER
694The name of the archive member; also known as
695.Ql Va % .
696.It Va .OODATE
697The list of sources for this target that were deemed out-of-date; also
698known as
699.Ql Va \&? .
700.It Va .PREFIX
701The file prefix of the target, containing only the file portion, no suffix
702or preceding directory components; also known as
703.Ql Va * .
704The suffix must be one of the known suffixes declared with
705.Ic .SUFFIXES
706or it will not be recognized.
707.It Va .TARGET
708The name of the target; also known as
709.Ql Va @ .
710For compatibility with other makes this is an alias for
711.Ic .ARCHIVE
712in archive member rules.
713.El
714.Pp
715The shorter forms
716.Ql ( Va > ,
717.Ql Va \&! ,
718.Ql Va < ,
719.Ql Va % ,
720.Ql Va \&? ,
721.Ql Va * ,
722and
723.Ql Va @ )
724are permitted for backward
725compatibility with historical makefiles and legacy POSIX make and are
726not recommended.
727.Pp
728Variants of these variables with the punctuation followed immediately by
729.Ql D
730or
731.Ql F ,
732e.g.
733.Ql Va $(@D) ,
734are legacy forms equivalent to using the
735.Ql :H
736and
737.Ql :T
738modifiers.
739These forms are accepted for compatibility with
740.At V
741makefiles and POSIX but are not recommended.
742.Pp
743Four of the local variables may be used in sources on dependency lines
744because they expand to the proper value for each target on the line.
745These variables are
746.Ql Va .TARGET ,
747.Ql Va .PREFIX ,
748.Ql Va .ARCHIVE ,
749and
750.Ql Va .MEMBER .
751.Ss Additional built-in variables
752In addition,
753.Nm
754sets or knows about the following variables:
755.Bl -tag -width .MAKEOVERRIDES
756.It Va \&$
757A single dollar sign
758.Ql \&$ ,
759i.e.
760.Ql \&$$
761expands to a single dollar
762sign.
763.It Va .ALLTARGETS
764The list of all targets encountered in the Makefile.
765If evaluated during
766Makefile parsing, lists only those targets encountered thus far.
767.It Va .CURDIR
768A path to the directory where
769.Nm
770was executed.
771Refer to the description of
772.Ql Ev PWD
773for more details.
774.It Va .INCLUDEDFROMDIR
775The directory of the file this Makefile was included from.
776.It Va .INCLUDEDFROMFILE
777The filename of the file this Makefile was included from.
778.It Ev MAKE
779The name that
780.Nm
781was executed with
782.Pq Va argv[0] .
783For compatibility
784.Nm
785also sets
786.Va .MAKE
787with the same value.
788The preferred variable to use is the environment variable
789.Ev MAKE
790because it is more compatible with other versions of
791.Nm
792and cannot be confused with the special target with the same name.
793.It Va .MAKE.ALWAYS_PASS_JOB_QUEUE
794Tells
795.Nm
796whether to pass the descriptors of the job token queue
797even if the target is not tagged with
798.Ic .MAKE
799The default is
800.Ql Pa yes
801for backwards compatability with
802.Fx 9.0
803and earlier.
804.It Va .MAKE.DEPENDFILE
805Names the makefile (default
806.Ql Pa .depend )
807from which generated dependencies are read.
808.It Va .MAKE.EXPAND_VARIABLES
809A boolean that controls the default behavior of the
810.Fl V
811option.
812If true, variable values printed with
813.Fl V
814are fully expanded; if false, the raw variable contents (which may
815include additional unexpanded variable references) are shown.
816.It Va .MAKE.EXPORTED
817The list of variables exported by
818.Nm .
819.It Va .MAKE.JOBS
820The argument to the
821.Fl j
822option.
823.It Va .MAKE.JOB.PREFIX
824If
825.Nm
826is run with
827.Ar j
828then output for each target is prefixed with a token
829.Ql --- target ---
830the first part of which can be controlled via
831.Va .MAKE.JOB.PREFIX .
832If
833.Va .MAKE.JOB.PREFIX
834is empty, no token is printed.
835.br
836For example:
837.Li .MAKE.JOB.PREFIX=${.newline}---${.MAKE:T}[${.MAKE.PID}]
838would produce tokens like
839.Ql ---make[1234] target ---
840making it easier to track the degree of parallelism being achieved.
841.It Ev MAKEFLAGS
842The environment variable
843.Ql Ev MAKEFLAGS
844may contain anything that
845may be specified on
846.Nm Ns 's
847command line.
848Anything specified on
849.Nm Ns 's
850command line is appended to the
851.Ql Ev MAKEFLAGS
852variable which is then
853entered into the environment for all programs which
854.Nm
855executes.
856.It Va .MAKE.LEVEL
857The recursion depth of
858.Nm .
859The initial instance of
860.Nm
861will be 0, and an incremented value is put into the environment
862to be seen by the next generation.
863This allows tests like:
864.Li .if ${.MAKE.LEVEL} == 0
865to protect things which should only be evaluated in the initial instance of
866.Nm .
867.It Va .MAKE.MAKEFILE_PREFERENCE
868The ordered list of makefile names
869(default
870.Ql Pa makefile ,
871.Ql Pa Makefile )
872that
873.Nm
874will look for.
875.It Va .MAKE.MAKEFILES
876The list of makefiles read by
877.Nm ,
878which is useful for tracking dependencies.
879Each makefile is recorded only once, regardless of the number of times read.
880.It Va .MAKE.MODE
881Processed after reading all makefiles.
882Can affect the mode that
883.Nm
884runs in.
885It can contain a number of keywords:
886.Bl -hang -width missing-filemon=bf.
887.It Pa compat
888Like
889.Fl B ,
890puts
891.Nm
892into "compat" mode.
893.It Pa meta
894Puts
895.Nm
896into "meta" mode, where meta files are created for each target
897to capture the command run, the output generated and if
898.Xr filemon 4
899is available, the system calls which are of interest to
900.Nm .
901The captured output can be very useful when diagnosing errors.
902.It Pa curdirOk= Ar bf
903Normally
904.Nm
905will not create .meta files in
906.Ql Va .CURDIR .
907This can be overridden by setting
908.Va bf
909to a value which represents True.
910.It Pa missing-meta= Ar bf
911If
912.Va bf
913is True, then a missing .meta file makes the target out-of-date.
914.It Pa missing-filemon= Ar bf
915If
916.Va bf
917is True, then missing filemon data makes the target out-of-date.
918.It Pa nofilemon
919Do not use
920.Xr filemon 4 .
921.It Pa env
922For debugging, it can be useful to include the environment
923in the .meta file.
924.It Pa verbose
925If in "meta" mode, print a clue about the target being built.
926This is useful if the build is otherwise running silently.
927The message printed the value of:
928.Va .MAKE.META.PREFIX .
929.It Pa ignore-cmd
930Some makefiles have commands which are simply not stable.
931This keyword causes them to be ignored for
932determining whether a target is out of date in "meta" mode.
933See also
934.Ic .NOMETA_CMP .
935.It Pa silent= Ar bf
936If
937.Va bf
938is True, when a .meta file is created, mark the target
939.Ic .SILENT .
940.El
941.It Va .MAKE.META.BAILIWICK
942In "meta" mode, provides a list of prefixes which
943match the directories controlled by
944.Nm .
945If a file that was generated outside of
946.Va .OBJDIR
947but within said bailiwick is missing,
948the current target is considered out-of-date.
949.It Va .MAKE.META.CREATED
950In "meta" mode, this variable contains a list of all the meta files
951updated.
952If not empty, it can be used to trigger processing of
953.Va .MAKE.META.FILES .
954.It Va .MAKE.META.FILES
955In "meta" mode, this variable contains a list of all the meta files
956used (updated or not).
957This list can be used to process the meta files to extract dependency
958information.
959.It Va .MAKE.META.IGNORE_PATHS
960Provides a list of path prefixes that should be ignored;
961because the contents are expected to change over time.
962The default list includes:
963.Ql Pa /dev /etc /proc /tmp /var/run /var/tmp
964.It Va .MAKE.META.IGNORE_PATTERNS
965Provides a list of patterns to match against pathnames.
966Ignore any that match.
967.It Va .MAKE.META.IGNORE_FILTER
968Provides a list of variable modifiers to apply to each pathname.
969Ignore if the expansion is an empty string.
970.It Va .MAKE.META.PREFIX
971Defines the message printed for each meta file updated in "meta verbose" mode.
972The default value is:
973.Dl Building ${.TARGET:H:tA}/${.TARGET:T}
974.It Va .MAKEOVERRIDES
975This variable is used to record the names of variables assigned to
976on the command line, so that they may be exported as part of
977.Ql Ev MAKEFLAGS .
978This behavior can be disabled by assigning an empty value to
979.Ql Va .MAKEOVERRIDES
980within a makefile.
981Extra variables can be exported from a makefile
982by appending their names to
983.Ql Va .MAKEOVERRIDES .
984.Ql Ev MAKEFLAGS
985is re-exported whenever
986.Ql Va .MAKEOVERRIDES
987is modified.
988.It Va .MAKE.PATH_FILEMON
989If
990.Nm
991was built with
992.Xr filemon 4
993support, this is set to the path of the device node.
994This allows makefiles to test for this support.
995.It Va .MAKE.PID
996The process-id of
997.Nm .
998.It Va .MAKE.PPID
999The parent process-id of
1000.Nm .
1001.It Va .MAKE.SAVE_DOLLARS
1002value should be a boolean that controls whether
1003.Ql $$
1004are preserved when doing
1005.Ql :=
1006assignments.
1007The default is false, for backwards compatibility.
1008Set to true for compatability with other makes.
1009If set to false,
1010.Ql $$
1011becomes
1012.Ql $
1013per normal evaluation rules.
1014.It Va MAKE_PRINT_VAR_ON_ERROR
1015When
1016.Nm
1017stops due to an error, it sets
1018.Ql Va .ERROR_TARGET
1019to the name of the target that failed,
1020.Ql Va .ERROR_CMD
1021to the commands of the failed target,
1022and in "meta" mode, it also sets
1023.Ql Va .ERROR_CWD
1024to the
1025.Xr getcwd 3 ,
1026and
1027.Ql Va .ERROR_META_FILE
1028to the path of the meta file (if any) describing the failed target.
1029It then prints its name and the value of
1030.Ql Va .CURDIR
1031as well as the value of any variables named in
1032.Ql Va MAKE_PRINT_VAR_ON_ERROR .
1033.It Va .newline
1034This variable is simply assigned a newline character as its value.
1035This allows expansions using the
1036.Cm \&:@
1037modifier to put a newline between
1038iterations of the loop rather than a space.
1039For example, the printing of
1040.Ql Va MAKE_PRINT_VAR_ON_ERROR
1041could be done as ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}.
1042.It Va .OBJDIR
1043A path to the directory where the targets are built.
1044Its value is determined by trying to
1045.Xr chdir 2
1046to the following directories in order and using the first match:
1047.Bl -enum
1048.It
1049.Ev ${MAKEOBJDIRPREFIX}${.CURDIR}
1050.Pp
1051(Only if
1052.Ql Ev MAKEOBJDIRPREFIX
1053is set in the environment or on the command line.)
1054.It
1055.Ev ${MAKEOBJDIR}
1056.Pp
1057(Only if
1058.Ql Ev MAKEOBJDIR
1059is set in the environment or on the command line.)
1060.It
1061.Ev ${.CURDIR} Ns Pa /obj. Ns Ev ${MACHINE}
1062.It
1063.Ev ${.CURDIR} Ns Pa /obj
1064.It
1065.Pa /usr/obj/ Ns Ev ${.CURDIR}
1066.It
1067.Ev ${.CURDIR}
1068.El
1069.Pp
1070Variable expansion is performed on the value before it's used,
1071so expressions such as
1072.Dl ${.CURDIR:S,^/usr/src,/var/obj,}
1073may be used.
1074This is especially useful with
1075.Ql Ev MAKEOBJDIR .
1076.Pp
1077.Ql Va .OBJDIR
1078may be modified in the makefile via the special target
1079.Ql Ic .OBJDIR .
1080In all cases,
1081.Nm
1082will
1083.Xr chdir 2
1084to the specified directory if it exists, and set
1085.Ql Va .OBJDIR
1086and
1087.Ql Ev PWD
1088to that directory before executing any targets.
1089.
1090.It Va .PARSEDIR
1091A path to the directory of the current
1092.Ql Pa Makefile
1093being parsed.
1094.It Va .PARSEFILE
1095The basename of the current
1096.Ql Pa Makefile
1097being parsed.
1098This variable and
1099.Ql Va .PARSEDIR
1100are both set only while the
1101.Ql Pa Makefiles
1102are being parsed.
1103If you want to retain their current values, assign them to a variable
1104using assignment with expansion:
1105.Pq Ql Cm \&:= .
1106.It Va .PATH
1107A variable that represents the list of directories that
1108.Nm
1109will search for files.
1110The search list should be updated using the target
1111.Ql Va .PATH
1112rather than the variable.
1113.It Ev PWD
1114Alternate path to the current directory.
1115.Nm
1116normally sets
1117.Ql Va .CURDIR
1118to the canonical path given by
1119.Xr getcwd 3 .
1120However, if the environment variable
1121.Ql Ev PWD
1122is set and gives a path to the current directory, then
1123.Nm
1124sets
1125.Ql Va .CURDIR
1126to the value of
1127.Ql Ev PWD
1128instead.
1129This behavior is disabled if
1130.Ql Ev MAKEOBJDIRPREFIX
1131is set or
1132.Ql Ev MAKEOBJDIR
1133contains a variable transform.
1134.Ql Ev PWD
1135is set to the value of
1136.Ql Va .OBJDIR
1137for all programs which
1138.Nm
1139executes.
1140.It Ev .TARGETS
1141The list of targets explicitly specified on the command line, if any.
1142.It Ev VPATH
1143Colon-separated
1144.Pq Dq \&:
1145lists of directories that
1146.Nm
1147will search for files.
1148The variable is supported for compatibility with old make programs only,
1149use
1150.Ql Va .PATH
1151instead.
1152.El
1153.Ss Variable modifiers
1154Variable expansion may be modified to select or modify each word of the
1155variable (where a
1156.Dq word
1157is white-space delimited sequence of characters).
1158The general format of a variable expansion is as follows:
1159.Pp
1160.Dl ${variable[:modifier[:...]]}
1161.Pp
1162Each modifier begins with a colon,
1163which may be escaped with a backslash
1164.Pq Ql \e .
1165.Pp
1166A set of modifiers can be specified via a variable, as follows:
1167.Pp
1168.Dl modifier_variable=modifier[:...]
1169.Dl ${variable:${modifier_variable}[:...]}
1170.Pp
1171In this case the first modifier in the modifier_variable does not
1172start with a colon, since that must appear in the referencing
1173variable.
1174If any of the modifiers in the modifier_variable contain a dollar sign
1175.Pq Ql $ ,
1176these must be doubled to avoid early expansion.
1177.Pp
1178The supported modifiers are:
1179.Bl -tag -width EEE
1180.It Cm \&:E
1181Replaces each word in the variable with its suffix.
1182.It Cm \&:H
1183Replaces each word in the variable with everything but the last component.
1184.It Cm \&:M Ns Ar pattern
1185Select only those words that match
1186.Ar pattern .
1187The standard shell wildcard characters
1188.Pf ( Ql * ,
1189.Ql \&? ,
1190and
1191.Ql Oo Oc )
1192may
1193be used.
1194The wildcard characters may be escaped with a backslash
1195.Pq Ql \e .
1196As a consequence of the way values are split into words, matched,
1197and then joined, a construct like
1198.Dl ${VAR:M*}
1199will normalize the inter-word spacing, removing all leading and
1200trailing space, and converting multiple consecutive spaces
1201to single spaces.
1202.
1203.It Cm \&:N Ns Ar pattern
1204This is identical to
1205.Ql Cm \&:M ,
1206but selects all words which do not match
1207.Ar pattern .
1208.It Cm \&:O
1209Order every word in variable alphabetically.
1210To sort words in
1211reverse order use the
1212.Ql Cm \&:O:[-1..1]
1213combination of modifiers.
1214.It Cm \&:Ox
1215Randomize words in variable.
1216The results will be different each time you are referring to the
1217modified variable; use the assignment with expansion
1218.Pq Ql Cm \&:=
1219to prevent such behavior.
1220For example,
1221.Bd -literal -offset indent
1222LIST=			uno due tre quattro
1223RANDOM_LIST=		${LIST:Ox}
1224STATIC_RANDOM_LIST:=	${LIST:Ox}
1225
1226all:
1227	@echo "${RANDOM_LIST}"
1228	@echo "${RANDOM_LIST}"
1229	@echo "${STATIC_RANDOM_LIST}"
1230	@echo "${STATIC_RANDOM_LIST}"
1231.Ed
1232may produce output similar to:
1233.Bd -literal -offset indent
1234quattro due tre uno
1235tre due quattro uno
1236due uno quattro tre
1237due uno quattro tre
1238.Ed
1239.It Cm \&:Q
1240Quotes every shell meta-character in the variable, so that it can be passed
1241safely to the shell.
1242.It Cm \&:q
1243Quotes every shell meta-character in the variable, and also doubles
1244.Sq $
1245characters so that it can be passed
1246safely through recursive invocations of
1247.Nm .
1248This is equivalent to:
1249.Sq \&:S/\e\&$/&&/g:Q .
1250.It Cm \&:R
1251Replaces each word in the variable with everything but its suffix.
1252.It Cm \&:range[=count]
1253The value is an integer sequence representing the words of the original
1254value, or the supplied
1255.Va count .
1256.It Cm \&:gmtime[=utc]
1257The value is a format string for
1258.Xr strftime 3 ,
1259using
1260.Xr gmtime 3 .
1261If a
1262.Va utc
1263value is not provided or is 0, the current time is used.
1264.It Cm \&:hash
1265Compute a 32-bit hash of the value and encode it as hex digits.
1266.It Cm \&:localtime[=utc]
1267The value is a format string for
1268.Xr strftime 3 ,
1269using
1270.Xr localtime 3 .
1271If a
1272.Va utc
1273value is not provided or is 0, the current time is used.
1274.It Cm \&:tA
1275Attempt to convert variable to an absolute path using
1276.Xr realpath 3 ,
1277if that fails, the value is unchanged.
1278.It Cm \&:tl
1279Converts variable to lower-case letters.
1280.It Cm \&:ts Ns Ar c
1281Words in the variable are normally separated by a space on expansion.
1282This modifier sets the separator to the character
1283.Ar c .
1284If
1285.Ar c
1286is omitted, then no separator is used.
1287The common escapes (including octal numeric codes), work as expected.
1288.It Cm \&:tu
1289Converts variable to upper-case letters.
1290.It Cm \&:tW
1291Causes the value to be treated as a single word
1292(possibly containing embedded white space).
1293See also
1294.Ql Cm \&:[*] .
1295.It Cm \&:tw
1296Causes the value to be treated as a sequence of
1297words delimited by white space.
1298See also
1299.Ql Cm \&:[@] .
1300.Sm off
1301.It Cm \&:S No \&/ Ar old_string No \&/ Ar new_string No \&/ Op Cm 1gW
1302.Sm on
1303Modify the first occurrence of
1304.Ar old_string
1305in the variable's value, replacing it with
1306.Ar new_string .
1307If a
1308.Ql g
1309is appended to the last slash of the pattern, all occurrences
1310in each word are replaced.
1311If a
1312.Ql 1
1313is appended to the last slash of the pattern, only the first word
1314is affected.
1315If a
1316.Ql W
1317is appended to the last slash of the pattern,
1318then the value is treated as a single word
1319(possibly containing embedded white space).
1320If
1321.Ar old_string
1322begins with a caret
1323.Pq Ql ^ ,
1324.Ar old_string
1325is anchored at the beginning of each word.
1326If
1327.Ar old_string
1328ends with a dollar sign
1329.Pq Ql \&$ ,
1330it is anchored at the end of each word.
1331Inside
1332.Ar new_string ,
1333an ampersand
1334.Pq Ql &
1335is replaced by
1336.Ar old_string
1337(without any
1338.Ql ^
1339or
1340.Ql \&$ ) .
1341Any character may be used as a delimiter for the parts of the modifier
1342string.
1343The anchoring, ampersand and delimiter characters may be escaped with a
1344backslash
1345.Pq Ql \e .
1346.Pp
1347Variable expansion occurs in the normal fashion inside both
1348.Ar old_string
1349and
1350.Ar new_string
1351with the single exception that a backslash is used to prevent the expansion
1352of a dollar sign
1353.Pq Ql \&$ ,
1354not a preceding dollar sign as is usual.
1355.Sm off
1356.It Cm \&:C No \&/ Ar pattern No \&/ Ar replacement No \&/ Op Cm 1gW
1357.Sm on
1358The
1359.Cm \&:C
1360modifier is just like the
1361.Cm \&:S
1362modifier except that the old and new strings, instead of being
1363simple strings, are an extended regular expression (see
1364.Xr regex 3 )
1365string
1366.Ar pattern
1367and an
1368.Xr ed 1 Ns \-style
1369string
1370.Ar replacement .
1371Normally, the first occurrence of the pattern
1372.Ar pattern
1373in each word of the value is substituted with
1374.Ar replacement .
1375The
1376.Ql 1
1377modifier causes the substitution to apply to at most one word; the
1378.Ql g
1379modifier causes the substitution to apply to as many instances of the
1380search pattern
1381.Ar pattern
1382as occur in the word or words it is found in; the
1383.Ql W
1384modifier causes the value to be treated as a single word
1385(possibly containing embedded white space).
1386Note that
1387.Ql 1
1388and
1389.Ql g
1390are orthogonal; the former specifies whether multiple words are
1391potentially affected, the latter whether multiple substitutions can
1392potentially occur within each affected word.
1393.Pp
1394As for the
1395.Cm \&:S
1396modifier, the
1397.Ar pattern
1398and
1399.Ar replacement
1400are subjected to variable expansion before being parsed as
1401regular expressions.
1402.It Cm \&:T
1403Replaces each word in the variable with its last component.
1404.It Cm \&:u
1405Remove adjacent duplicate words (like
1406.Xr uniq 1 ) .
1407.Sm off
1408.It Cm \&:\&? Ar true_string Cm \&: Ar false_string
1409.Sm on
1410If the variable name (not its value), when parsed as a .if conditional
1411expression, evaluates to true, return as its value the
1412.Ar true_string ,
1413otherwise return the
1414.Ar false_string .
1415Since the variable name is used as the expression, \&:\&? must be the
1416first modifier after the variable name itself - which will, of course,
1417usually contain variable expansions.
1418A common error is trying to use expressions like
1419.Dl ${NUMBERS:M42:?match:no}
1420which actually tests defined(NUMBERS),
1421to determine is any words match "42" you need to use something like:
1422.Dl ${"${NUMBERS:M42}" != \&"\&":?match:no} .
1423.It Ar :old_string=new_string
1424This is the
1425.At V
1426style variable substitution.
1427It must be the last modifier specified.
1428If
1429.Ar old_string
1430or
1431.Ar new_string
1432do not contain the pattern matching character
1433.Ar %
1434then it is assumed that they are
1435anchored at the end of each word, so only suffixes or entire
1436words may be replaced.
1437Otherwise
1438.Ar %
1439is the substring of
1440.Ar old_string
1441to be replaced in
1442.Ar new_string .
1443If only
1444.Ar old_string
1445contains the pattern matching character
1446.Ar % ,
1447and
1448.Ar old_string
1449matches, then the result is the
1450.Ar new_string .
1451If only the
1452.Ar new_string
1453contains the pattern matching character
1454.Ar % ,
1455then it is not treated specially and it is printed as a literal
1456.Ar %
1457on match.
1458If there is more than one pattern matching character
1459.Ar ( % )
1460in either the
1461.Ar new_string
1462or
1463.Ar old_string ,
1464only the first instance is treated specially (as the pattern character);
1465all subsequent instances are treated as regular characters
1466.Pp
1467Variable expansion occurs in the normal fashion inside both
1468.Ar old_string
1469and
1470.Ar new_string
1471with the single exception that a backslash is used to prevent the
1472expansion of a dollar sign
1473.Pq Ql \&$ ,
1474not a preceding dollar sign as is usual.
1475.Sm off
1476.It Cm \&:@ Ar temp Cm @ Ar string Cm @
1477.Sm on
1478This is the loop expansion mechanism from the OSF Development
1479Environment (ODE) make.
1480Unlike
1481.Cm \&.for
1482loops expansion occurs at the time of
1483reference.
1484Assign
1485.Ar temp
1486to each word in the variable and evaluate
1487.Ar string .
1488The ODE convention is that
1489.Ar temp
1490should start and end with a period.
1491For example.
1492.Dl ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}
1493.Pp
1494However a single character variable is often more readable:
1495.Dl ${MAKE_PRINT_VAR_ON_ERROR:@v@$v='${$v}'${.newline}@}
1496.It Cm \&:_[=var]
1497Save the current variable value in
1498.Ql $_
1499or the named
1500.Va var
1501for later reference.
1502Example usage:
1503.Bd -literal -offset indent
1504M_cmpv.units = 1 1000 1000000
1505M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \&\\
1506\\* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh
1507
1508.Dv .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}}
1509
1510.Ed
1511Here
1512.Ql $_
1513is used to save the result of the
1514.Ql :S
1515modifier which is later referenced using the index values from
1516.Ql :range .
1517.It Cm \&:U Ns Ar newval
1518If the variable is undefined
1519.Ar newval
1520is the value.
1521If the variable is defined, the existing value is returned.
1522This is another ODE make feature.
1523It is handy for setting per-target CFLAGS for instance:
1524.Dl ${_${.TARGET:T}_CFLAGS:U${DEF_CFLAGS}}
1525If a value is only required if the variable is undefined, use:
1526.Dl ${VAR:D:Unewval}
1527.It Cm \&:D Ns Ar newval
1528If the variable is defined
1529.Ar newval
1530is the value.
1531.It Cm \&:L
1532The name of the variable is the value.
1533.It Cm \&:P
1534The path of the node which has the same name as the variable
1535is the value.
1536If no such node exists or its path is null, then the
1537name of the variable is used.
1538In order for this modifier to work, the name (node) must at least have
1539appeared on the rhs of a dependency.
1540.Sm off
1541.It Cm \&:\&! Ar cmd Cm \&!
1542.Sm on
1543The output of running
1544.Ar cmd
1545is the value.
1546.It Cm \&:sh
1547If the variable is non-empty it is run as a command and the output
1548becomes the new value.
1549.It Cm \&::= Ns Ar str
1550The variable is assigned the value
1551.Ar str
1552after substitution.
1553This modifier and its variations are useful in
1554obscure situations such as wanting to set a variable when shell commands
1555are being parsed.
1556These assignment modifiers always expand to
1557nothing, so if appearing in a rule line by themselves should be
1558preceded with something to keep
1559.Nm
1560happy.
1561.Pp
1562The
1563.Ql Cm \&::
1564helps avoid false matches with the
1565.At V
1566style
1567.Cm \&:=
1568modifier and since substitution always occurs the
1569.Cm \&::=
1570form is vaguely appropriate.
1571.It Cm \&::?= Ns Ar str
1572As for
1573.Cm \&::=
1574but only if the variable does not already have a value.
1575.It Cm \&::+= Ns Ar str
1576Append
1577.Ar str
1578to the variable.
1579.It Cm \&::!= Ns Ar cmd
1580Assign the output of
1581.Ar cmd
1582to the variable.
1583.It Cm \&:\&[ Ns Ar range Ns Cm \&]
1584Selects one or more words from the value,
1585or performs other operations related to the way in which the
1586value is divided into words.
1587.Pp
1588Ordinarily, a value is treated as a sequence of words
1589delimited by white space.
1590Some modifiers suppress this behavior,
1591causing a value to be treated as a single word
1592(possibly containing embedded white space).
1593An empty value, or a value that consists entirely of white-space,
1594is treated as a single word.
1595For the purposes of the
1596.Ql Cm \&:[]
1597modifier, the words are indexed both forwards using positive integers
1598(where index 1 represents the first word),
1599and backwards using negative integers
1600(where index \-1 represents the last word).
1601.Pp
1602The
1603.Ar range
1604is subjected to variable expansion, and the expanded result is
1605then interpreted as follows:
1606.Bl -tag -width index
1607.\" :[n]
1608.It Ar index
1609Selects a single word from the value.
1610.\" :[start..end]
1611.It Ar start Ns Cm \&.. Ns Ar end
1612Selects all words from
1613.Ar start
1614to
1615.Ar end ,
1616inclusive.
1617For example,
1618.Ql Cm \&:[2..-1]
1619selects all words from the second word to the last word.
1620If
1621.Ar start
1622is greater than
1623.Ar end ,
1624then the words are output in reverse order.
1625For example,
1626.Ql Cm \&:[-1..1]
1627selects all the words from last to first.
1628.\" :[*]
1629.It Cm \&*
1630Causes subsequent modifiers to treat the value as a single word
1631(possibly containing embedded white space).
1632Analogous to the effect of
1633\&"$*\&"
1634in Bourne shell.
1635.\" :[0]
1636.It 0
1637Means the same as
1638.Ql Cm \&:[*] .
1639.\" :[*]
1640.It Cm \&@
1641Causes subsequent modifiers to treat the value as a sequence of words
1642delimited by white space.
1643Analogous to the effect of
1644\&"$@\&"
1645in Bourne shell.
1646.\" :[#]
1647.It Cm \&#
1648Returns the number of words in the value.
1649.El \" :[range]
1650.El
1651.Sh INCLUDE STATEMENTS, CONDITIONALS AND FOR LOOPS
1652Makefile inclusion, conditional structures and for loops  reminiscent
1653of the C programming language are provided in
1654.Nm .
1655All such structures are identified by a line beginning with a single
1656dot
1657.Pq Ql \&.
1658character.
1659Files are included with either
1660.Cm \&.include \&< Ns Ar file Ns Cm \&>
1661or
1662.Cm \&.include \&\*q Ns Ar file Ns Cm \&\*q .
1663Variables between the angle brackets or double quotes are expanded
1664to form the file name.
1665If angle brackets are used, the included makefile is expected to be in
1666the system makefile directory.
1667If double quotes are used, the including makefile's directory and any
1668directories specified using the
1669.Fl I
1670option are searched before the system
1671makefile directory.
1672For compatibility with other versions of
1673.Nm
1674.Ql include file ...
1675is also accepted.
1676.Pp
1677If the include statement is written as
1678.Cm .-include
1679or as
1680.Cm .sinclude
1681then errors locating and/or opening include files are ignored.
1682.Pp
1683If the include statement is written as
1684.Cm .dinclude
1685not only are errors locating and/or opening include files ignored,
1686but stale dependencies within the included file will be ignored
1687just like
1688.Va .MAKE.DEPENDFILE .
1689.Pp
1690Conditional expressions are also preceded by a single dot as the first
1691character of a line.
1692The possible conditionals are as follows:
1693.Bl -tag -width Ds
1694.It Ic .error Ar message
1695The message is printed along with the name of the makefile and line number,
1696then
1697.Nm
1698will exit.
1699.It Ic .export Ar variable ...
1700Export the specified global variable.
1701If no variable list is provided, all globals are exported
1702except for internal variables (those that start with
1703.Ql \&. ) .
1704This is not affected by the
1705.Fl X
1706flag, so should be used with caution.
1707For compatibility with other
1708.Nm
1709programs
1710.Ql export variable=value
1711is also accepted.
1712.Pp
1713Appending a variable name to
1714.Va .MAKE.EXPORTED
1715is equivalent to exporting a variable.
1716.It Ic .export-env Ar variable ...
1717The same as
1718.Ql .export ,
1719except that the variable is not appended to
1720.Va .MAKE.EXPORTED .
1721This allows exporting a value to the environment which is different from that
1722used by
1723.Nm
1724internally.
1725.It Ic .export-literal Ar variable ...
1726The same as
1727.Ql .export-env ,
1728except that variables in the value are not expanded.
1729.It Ic .info Ar message
1730The message is printed along with the name of the makefile and line number.
1731.It Ic .undef Ar variable
1732Un-define the specified global variable.
1733Only global variables may be un-defined.
1734.It Ic .unexport Ar variable ...
1735The opposite of
1736.Ql .export .
1737The specified global
1738.Va variable
1739will be removed from
1740.Va .MAKE.EXPORTED .
1741If no variable list is provided, all globals are unexported,
1742and
1743.Va .MAKE.EXPORTED
1744deleted.
1745.It Ic .unexport-env
1746Unexport all globals previously exported and
1747clear the environment inherited from the parent.
1748This operation will cause a memory leak of the original environment,
1749so should be used sparingly.
1750Testing for
1751.Va .MAKE.LEVEL
1752being 0, would make sense.
1753Also note that any variables which originated in the parent environment
1754should be explicitly preserved if desired.
1755For example:
1756.Bd -literal -offset indent
1757.Li .if ${.MAKE.LEVEL} == 0
1758PATH := ${PATH}
1759.Li .unexport-env
1760.Li .export PATH
1761.Li .endif
1762.Pp
1763.Ed
1764Would result in an environment containing only
1765.Ql Ev PATH ,
1766which is the minimal useful environment.
1767Actually
1768.Ql Ev .MAKE.LEVEL
1769will also be pushed into the new environment.
1770.It Ic .warning Ar message
1771The message prefixed by
1772.Ql Pa warning:
1773is printed along with the name of the makefile and line number.
1774.It Ic \&.if Oo \&! Oc Ns Ar expression Op Ar operator expression ...
1775Test the value of an expression.
1776.It Ic .ifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1777Test the value of a variable.
1778.It Ic .ifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1779Test the value of a variable.
1780.It Ic .ifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1781Test the target being built.
1782.It Ic .ifnmake Oo \&! Ns Oc Ar target Op Ar operator target ...
1783Test the target being built.
1784.It Ic .else
1785Reverse the sense of the last conditional.
1786.It Ic .elif Oo \&! Ns Oc Ar expression Op Ar operator expression ...
1787A combination of
1788.Ql Ic .else
1789followed by
1790.Ql Ic .if .
1791.It Ic .elifdef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1792A combination of
1793.Ql Ic .else
1794followed by
1795.Ql Ic .ifdef .
1796.It Ic .elifndef Oo \&! Oc Ns Ar variable Op Ar operator variable ...
1797A combination of
1798.Ql Ic .else
1799followed by
1800.Ql Ic .ifndef .
1801.It Ic .elifmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1802A combination of
1803.Ql Ic .else
1804followed by
1805.Ql Ic .ifmake .
1806.It Ic .elifnmake Oo \&! Oc Ns Ar target Op Ar operator target ...
1807A combination of
1808.Ql Ic .else
1809followed by
1810.Ql Ic .ifnmake .
1811.It Ic .endif
1812End the body of the conditional.
1813.El
1814.Pp
1815The
1816.Ar operator
1817may be any one of the following:
1818.Bl -tag -width "Cm XX"
1819.It Cm \&|\&|
1820Logical OR.
1821.It Cm \&&&
1822Logical
1823.Tn AND ;
1824of higher precedence than
1825.Dq \&|\&| .
1826.El
1827.Pp
1828As in C,
1829.Nm
1830will only evaluate a conditional as far as is necessary to determine
1831its value.
1832Parentheses may be used to change the order of evaluation.
1833The boolean operator
1834.Ql Ic \&!
1835may be used to logically negate an entire
1836conditional.
1837It is of higher precedence than
1838.Ql Ic \&&& .
1839.Pp
1840The value of
1841.Ar expression
1842may be any of the following:
1843.Bl -tag -width defined
1844.It Ic defined
1845Takes a variable name as an argument and evaluates to true if the variable
1846has been defined.
1847.It Ic make
1848Takes a target name as an argument and evaluates to true if the target
1849was specified as part of
1850.Nm Ns 's
1851command line or was declared the default target (either implicitly or
1852explicitly, see
1853.Va .MAIN )
1854before the line containing the conditional.
1855.It Ic empty
1856Takes a variable, with possible modifiers, and evaluates to true if
1857the expansion of the variable would result in an empty string.
1858.It Ic exists
1859Takes a file name as an argument and evaluates to true if the file exists.
1860The file is searched for on the system search path (see
1861.Va .PATH ) .
1862.It Ic target
1863Takes a target name as an argument and evaluates to true if the target
1864has been defined.
1865.It Ic commands
1866Takes a target name as an argument and evaluates to true if the target
1867has been defined and has commands associated with it.
1868.El
1869.Pp
1870.Ar Expression
1871may also be an arithmetic or string comparison.
1872Variable expansion is
1873performed on both sides of the comparison, after which the integral
1874values are compared.
1875A value is interpreted as hexadecimal if it is
1876preceded by 0x, otherwise it is decimal; octal numbers are not supported.
1877The standard C relational operators are all supported.
1878If after
1879variable expansion, either the left or right hand side of a
1880.Ql Ic ==
1881or
1882.Ql Ic "!="
1883operator is not an integral value, then
1884string comparison is performed between the expanded
1885variables.
1886If no relational operator is given, it is assumed that the expanded
1887variable is being compared against 0 or an empty string in the case
1888of a string comparison.
1889.Pp
1890When
1891.Nm
1892is evaluating one of these conditional expressions, and it encounters
1893a (white-space separated) word it doesn't recognize, either the
1894.Dq make
1895or
1896.Dq defined
1897expression is applied to it, depending on the form of the conditional.
1898If the form is
1899.Ql Ic .ifdef ,
1900.Ql Ic .ifndef ,
1901or
1902.Ql Ic .if
1903the
1904.Dq defined
1905expression is applied.
1906Similarly, if the form is
1907.Ql Ic .ifmake
1908or
1909.Ql Ic .ifnmake ,
1910the
1911.Dq make
1912expression is applied.
1913.Pp
1914If the conditional evaluates to true the parsing of the makefile continues
1915as before.
1916If it evaluates to false, the following lines are skipped.
1917In both cases this continues until a
1918.Ql Ic .else
1919or
1920.Ql Ic .endif
1921is found.
1922.Pp
1923For loops are typically used to apply a set of rules to a list of files.
1924The syntax of a for loop is:
1925.Pp
1926.Bl -tag -compact -width Ds
1927.It Ic \&.for Ar variable Oo Ar variable ... Oc Ic in Ar expression
1928.It Aq make-rules
1929.It Ic \&.endfor
1930.El
1931.Pp
1932After the for
1933.Ic expression
1934is evaluated, it is split into words.
1935On each iteration of the loop, one word is taken and assigned to each
1936.Ic variable ,
1937in order, and these
1938.Ic variables
1939are substituted into the
1940.Ic make-rules
1941inside the body of the for loop.
1942The number of words must come out even; that is, if there are three
1943iteration variables, the number of words provided must be a multiple
1944of three.
1945.Sh COMMENTS
1946Comments begin with a hash
1947.Pq Ql \&#
1948character, anywhere but in a shell
1949command line, and continue to the end of an unescaped new line.
1950.Sh SPECIAL SOURCES (ATTRIBUTES)
1951.Bl -tag -width .IGNOREx
1952.It Ic .EXEC
1953Target is never out of date, but always execute commands anyway.
1954.It Ic .IGNORE
1955Ignore any errors from the commands associated with this target, exactly
1956as if they all were preceded by a dash
1957.Pq Ql \- .
1958.\" .It Ic .INVISIBLE
1959.\" XXX
1960.\" .It Ic .JOIN
1961.\" XXX
1962.It Ic .MADE
1963Mark all sources of this target as being up-to-date.
1964.It Ic .MAKE
1965Execute the commands associated with this target even if the
1966.Fl n
1967or
1968.Fl t
1969options were specified.
1970Normally used to mark recursive
1971.Nm Ns s .
1972.It Ic .META
1973Create a meta file for the target, even if it is flagged as
1974.Ic .PHONY ,
1975.Ic .MAKE ,
1976or
1977.Ic .SPECIAL .
1978Usage in conjunction with
1979.Ic .MAKE
1980is the most likely case.
1981In "meta" mode, the target is out-of-date if the meta file is missing.
1982.It Ic .NOMETA
1983Do not create a meta file for the target.
1984Meta files are also not created for
1985.Ic .PHONY ,
1986.Ic .MAKE ,
1987or
1988.Ic .SPECIAL
1989targets.
1990.It Ic .NOMETA_CMP
1991Ignore differences in commands when deciding if target is out of date.
1992This is useful if the command contains a value which always changes.
1993If the number of commands change, though, the target will still be out of date.
1994The same effect applies to any command line that uses the variable
1995.Va .OODATE ,
1996which can be used for that purpose even when not otherwise needed or desired:
1997.Bd -literal -offset indent
1998
1999skip-compare-for-some:
2000	@echo this will be compared
2001	@echo this will not ${.OODATE:M.NOMETA_CMP}
2002	@echo this will also be compared
2003
2004.Ed
2005The
2006.Cm \&:M
2007pattern suppresses any expansion of the unwanted variable.
2008.It Ic .NOPATH
2009Do not search for the target in the directories specified by
2010.Ic .PATH .
2011.It Ic .NOTMAIN
2012Normally
2013.Nm
2014selects the first target it encounters as the default target to be built
2015if no target was specified.
2016This source prevents this target from being selected.
2017.It Ic .OPTIONAL
2018If a target is marked with this attribute and
2019.Nm
2020can't figure out how to create it, it will ignore this fact and assume
2021the file isn't needed or already exists.
2022.It Ic .PHONY
2023The target does not
2024correspond to an actual file; it is always considered to be out of date,
2025and will not be created with the
2026.Fl t
2027option.
2028Suffix-transformation rules are not applied to
2029.Ic .PHONY
2030targets.
2031.It Ic .PRECIOUS
2032When
2033.Nm
2034is interrupted, it normally removes any partially made targets.
2035This source prevents the target from being removed.
2036.It Ic .RECURSIVE
2037Synonym for
2038.Ic .MAKE .
2039.It Ic .SILENT
2040Do not echo any of the commands associated with this target, exactly
2041as if they all were preceded by an at sign
2042.Pq Ql @ .
2043.It Ic .USE
2044Turn the target into
2045.Nm Ns 's
2046version of a macro.
2047When the target is used as a source for another target, the other target
2048acquires the commands, sources, and attributes (except for
2049.Ic .USE )
2050of the
2051source.
2052If the target already has commands, the
2053.Ic .USE
2054target's commands are appended
2055to them.
2056.It Ic .USEBEFORE
2057Exactly like
2058.Ic .USE ,
2059but prepend the
2060.Ic .USEBEFORE
2061target commands to the target.
2062.It Ic .WAIT
2063If
2064.Ic .WAIT
2065appears in a dependency line, the sources that precede it are
2066made before the sources that succeed it in the line.
2067Since the dependents of files are not made until the file itself
2068could be made, this also stops the dependents being built unless they
2069are needed for another branch of the dependency tree.
2070So given:
2071.Bd -literal
2072x: a .WAIT b
2073	echo x
2074a:
2075	echo a
2076b: b1
2077	echo b
2078b1:
2079	echo b1
2080
2081.Ed
2082the output is always
2083.Ql a ,
2084.Ql b1 ,
2085.Ql b ,
2086.Ql x .
2087.br
2088The ordering imposed by
2089.Ic .WAIT
2090is only relevant for parallel makes.
2091.El
2092.Sh SPECIAL TARGETS
2093Special targets may not be included with other targets, i.e. they must be
2094the only target specified.
2095.Bl -tag -width .BEGINx
2096.It Ic .BEGIN
2097Any command lines attached to this target are executed before anything
2098else is done.
2099.It Ic .DEFAULT
2100This is sort of a
2101.Ic .USE
2102rule for any target (that was used only as a
2103source) that
2104.Nm
2105can't figure out any other way to create.
2106Only the shell script is used.
2107The
2108.Ic .IMPSRC
2109variable of a target that inherits
2110.Ic .DEFAULT Ns 's
2111commands is set
2112to the target's own name.
2113.It Ic .DELETE_ON_ERROR
2114If this target is present in the makefile, it globally causes make to
2115delete targets whose commands fail.
2116(By default, only targets whose commands are interrupted during
2117execution are deleted.
2118This is the historical behavior.)
2119This setting can be used to help prevent half-finished or malformed
2120targets from being left around and corrupting future rebuilds.
2121.It Ic .END
2122Any command lines attached to this target are executed after everything
2123else is done.
2124.It Ic .ERROR
2125Any command lines attached to this target are executed when another target fails.
2126The
2127.Ic .ERROR_TARGET
2128variable is set to the target that failed.
2129See also
2130.Ic MAKE_PRINT_VAR_ON_ERROR .
2131.It Ic .IGNORE
2132Mark each of the sources with the
2133.Ic .IGNORE
2134attribute.
2135If no sources are specified, this is the equivalent of specifying the
2136.Fl i
2137option.
2138.It Ic .INTERRUPT
2139If
2140.Nm
2141is interrupted, the commands for this target will be executed.
2142.It Ic .MAIN
2143If no target is specified when
2144.Nm
2145is invoked, this target will be built.
2146.It Ic .MAKEFLAGS
2147This target provides a way to specify flags for
2148.Nm
2149when the makefile is used.
2150The flags are as if typed to the shell, though the
2151.Fl f
2152option will have
2153no effect.
2154.\" XXX: NOT YET!!!!
2155.\" .It Ic .NOTPARALLEL
2156.\" The named targets are executed in non parallel mode.
2157.\" If no targets are
2158.\" specified, then all targets are executed in non parallel mode.
2159.It Ic .NOPATH
2160Apply the
2161.Ic .NOPATH
2162attribute to any specified sources.
2163.It Ic .NOTPARALLEL
2164Disable parallel mode.
2165.It Ic .NO_PARALLEL
2166Synonym for
2167.Ic .NOTPARALLEL ,
2168for compatibility with other pmake variants.
2169.It Ic .OBJDIR
2170The source is a new value for
2171.Ql Va .OBJDIR .
2172If it exists,
2173.Nm
2174will
2175.Xr chdir 2
2176to it and update the value of
2177.Ql Va .OBJDIR .
2178.It Ic .ORDER
2179The named targets are made in sequence.
2180This ordering does not add targets to the list of targets to be made.
2181Since the dependents of a target do not get built until the target itself
2182could be built, unless
2183.Ql a
2184is built by another part of the dependency graph,
2185the following is a dependency loop:
2186.Bd -literal
2187\&.ORDER: b a
2188b: a
2189.Ed
2190.Pp
2191The ordering imposed by
2192.Ic .ORDER
2193is only relevant for parallel makes.
2194.\" XXX: NOT YET!!!!
2195.\" .It Ic .PARALLEL
2196.\" The named targets are executed in parallel mode.
2197.\" If no targets are
2198.\" specified, then all targets are executed in parallel mode.
2199.It Ic .PATH
2200The sources are directories which are to be searched for files not
2201found in the current directory.
2202If no sources are specified, any previously specified directories are
2203deleted.
2204If the source is the special
2205.Ic .DOTLAST
2206target, then the current working
2207directory is searched last.
2208.It Ic .PATH. Ns Va suffix
2209Like
2210.Ic .PATH
2211but applies only to files with a particular suffix.
2212The suffix must have been previously declared with
2213.Ic .SUFFIXES .
2214.It Ic .PHONY
2215Apply the
2216.Ic .PHONY
2217attribute to any specified sources.
2218.It Ic .PRECIOUS
2219Apply the
2220.Ic .PRECIOUS
2221attribute to any specified sources.
2222If no sources are specified, the
2223.Ic .PRECIOUS
2224attribute is applied to every
2225target in the file.
2226.It Ic .SHELL
2227Sets the shell that
2228.Nm
2229will use to execute commands.
2230The sources are a set of
2231.Ar field=value
2232pairs.
2233.Bl -tag -width hasErrCtls
2234.It Ar name
2235This is the minimal specification, used to select one of the built-in
2236shell specs;
2237.Ar sh ,
2238.Ar ksh ,
2239and
2240.Ar csh .
2241.It Ar path
2242Specifies the path to the shell.
2243.It Ar hasErrCtl
2244Indicates whether the shell supports exit on error.
2245.It Ar check
2246The command to turn on error checking.
2247.It Ar ignore
2248The command to disable error checking.
2249.It Ar echo
2250The command to turn on echoing of commands executed.
2251.It Ar quiet
2252The command to turn off echoing of commands executed.
2253.It Ar filter
2254The output to filter after issuing the
2255.Ar quiet
2256command.
2257It is typically identical to
2258.Ar quiet .
2259.It Ar errFlag
2260The flag to pass the shell to enable error checking.
2261.It Ar echoFlag
2262The flag to pass the shell to enable command echoing.
2263.It Ar newline
2264The string literal to pass the shell that results in a single newline
2265character when used outside of any quoting characters.
2266.El
2267Example:
2268.Bd -literal
2269\&.SHELL: name=ksh path=/bin/ksh hasErrCtl=true \e
2270	check="set \-e" ignore="set +e" \e
2271	echo="set \-v" quiet="set +v" filter="set +v" \e
2272	echoFlag=v errFlag=e newline="'\en'"
2273.Ed
2274.It Ic .SILENT
2275Apply the
2276.Ic .SILENT
2277attribute to any specified sources.
2278If no sources are specified, the
2279.Ic .SILENT
2280attribute is applied to every
2281command in the file.
2282.It Ic .STALE
2283This target gets run when a dependency file contains stale entries, having
2284.Va .ALLSRC
2285set to the name of that dependency file.
2286.It Ic .SUFFIXES
2287Each source specifies a suffix to
2288.Nm .
2289If no sources are specified, any previously specified suffixes are deleted.
2290It allows the creation of suffix-transformation rules.
2291.Pp
2292Example:
2293.Bd -literal
2294\&.SUFFIXES: .o
2295\&.c.o:
2296	cc \-o ${.TARGET} \-c ${.IMPSRC}
2297.Ed
2298.El
2299.Sh ENVIRONMENT
2300.Nm
2301uses the following environment variables, if they exist:
2302.Ev MACHINE ,
2303.Ev MACHINE_ARCH ,
2304.Ev MAKE ,
2305.Ev MAKEFLAGS ,
2306.Ev MAKEOBJDIR ,
2307.Ev MAKEOBJDIRPREFIX ,
2308.Ev MAKESYSPATH ,
2309.Ev PWD ,
2310and
2311.Ev TMPDIR .
2312.Pp
2313.Ev MAKEOBJDIRPREFIX
2314and
2315.Ev MAKEOBJDIR
2316may only be set in the environment or on the command line to
2317.Nm
2318and not as makefile variables;
2319see the description of
2320.Ql Va .OBJDIR
2321for more details.
2322.Sh FILES
2323.Bl -tag -width /usr/share/mk -compact
2324.It .depend
2325list of dependencies
2326.It Makefile
2327list of dependencies
2328.It makefile
2329list of dependencies
2330.It sys.mk
2331system makefile
2332.It /usr/share/mk
2333system makefile directory
2334.El
2335.Sh COMPATIBILITY
2336The basic make syntax is compatible between different versions of make;
2337however the special variables, variable modifiers and conditionals are not.
2338.Ss Older versions
2339An incomplete list of changes in older versions of
2340.Nm :
2341.Pp
2342The way that .for loop variables are substituted changed after
2343.Nx 5.0
2344so that they still appear to be variable expansions.
2345In particular this stops them being treated as syntax, and removes some
2346obscure problems using them in .if statements.
2347.Pp
2348The way that parallel makes are scheduled changed in
2349.Nx 4.0
2350so that .ORDER and .WAIT apply recursively to the dependent nodes.
2351The algorithms used may change again in the future.
2352.Ss Other make dialects
2353Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not
2354support most of the features of
2355.Nm
2356as described in this manual.
2357Most notably:
2358.Bl -bullet -offset indent
2359.It
2360The
2361.Ic .WAIT
2362and
2363.Ic .ORDER
2364declarations and most functionality pertaining to parallelization.
2365(GNU make supports parallelization but lacks these features needed to
2366control it effectively.)
2367.It
2368Directives, including for loops and conditionals and most of the
2369forms of include files.
2370(GNU make has its own incompatible and less powerful syntax for
2371conditionals.)
2372.It
2373All built-in variables that begin with a dot.
2374.It
2375Most of the special sources and targets that begin with a dot,
2376with the notable exception of
2377.Ic .PHONY ,
2378.Ic .PRECIOUS ,
2379and
2380.Ic .SUFFIXES .
2381.It
2382Variable modifiers, except for the
2383.Dl :old=new
2384string substitution, which does not portably support globbing with
2385.Ql %
2386and historically only works on declared suffixes.
2387.It
2388The
2389.Ic $>
2390variable even in its short form; most makes support this functionality
2391but its name varies.
2392.El
2393.Pp
2394Some features are somewhat more portable, such as assignment with
2395.Ic += ,
2396.Ic ?= ,
2397and
2398.Ic != .
2399The
2400.Ic .PATH
2401functionality is based on an older feature
2402.Ic VPATH
2403found in GNU make and many versions of SVR4 make; however,
2404historically its behavior is too ill-defined (and too buggy) to rely
2405upon.
2406.Pp
2407The
2408.Ic $@
2409and
2410.Ic $<
2411variables are more or less universally portable, as is the
2412.Ic $(MAKE)
2413variable.
2414Basic use of suffix rules (for files only in the current directory,
2415not trying to chain transformations together, etc.) is also reasonably
2416portable.
2417.Sh SEE ALSO
2418.Xr mkdep 1 ,
2419.Xr style.Makefile 5
2420.Sh HISTORY
2421A
2422.Nm
2423command appeared in
2424.At v7 .
2425This
2426.Nm
2427implementation is based on Adam De Boor's pmake program which was written
2428for Sprite at Berkeley.
2429It was designed to be a parallel distributed make running jobs on different
2430machines using a daemon called
2431.Dq customs .
2432.Pp
2433Historically the target/dependency
2434.Dq FRC
2435has been used to FoRCe rebuilding (since the target/dependency
2436does not exist... unless someone creates an
2437.Dq FRC
2438file).
2439.Sh BUGS
2440The
2441.Nm
2442syntax is difficult to parse without actually acting on the data.
2443For instance, finding the end of a variable's use should involve scanning
2444each of the modifiers, using the correct terminator for each field.
2445In many places
2446.Nm
2447just counts {} and () in order to find the end of a variable expansion.
2448.Pp
2449There is no way of escaping a space character in a filename.
2450