freebsd-dev/usr.bin/make/make.1

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.\"	@(#)make.1	8.8 (Berkeley) 6/13/95
.\" $FreeBSD$
.\"
.Dd May 30, 2012
.Dt MAKE 1
.Os
.Sh NAME
.Nm make
.Nd maintain program dependencies
.Sh SYNOPSIS
.Nm
.Op Fl ABPSXeiknpqrstv
.Op Fl C Ar directory
.Op Fl D Ar variable
.Op Fl d Ar flags
.Op Fl E Ar variable
.Op Fl f Ar makefile
.Op Fl I Ar directory
.Bk -words
.Op Fl j Ar max_jobs
.Op Fl m Ar directory
.Ek
.Op Fl V Ar variable
.Op Fl x Ar warning_options
.Op Ar variable Ns No = Ns Ar value
.Op Ar target ...
.Sh DESCRIPTION
The
.Nm
utility is a program designed to simplify the maintenance of other programs.
Its input is a list of specifications
describing dependency relationships between the generation of
files and programs.
.Pp
First of all, the initial list of specifications will be read
from the system makefile,
.Pa sys.mk ,
unless inhibited with the
.Fl r
option.
The standard
.Pa sys.mk
as shipped with
.Fx
also handles
.Xr make.conf 5 ,
the default path to which
can be altered via the
.Nm
variable
.Va __MAKE_CONF .
.Pp
Then the first of
.Pa BSDmakefile ,
.Pa makefile ,
and
.Pa Makefile
that can be found in the current directory, object directory (see
.Va .OBJDIR ) ,
or search path (see the
.Fl I
option)
will be read for the main list of dependency specifications.
A different makefile or list of them can be supplied via the
.Fl f
option(s).
Finally, if the file
.Pa .depend
can be found in any of the aforesaid locations, it will also be read (see
.Xr mkdep 1 ) .
.Pp
When
.Nm
searches for a makefile, its name takes precedence over its location.
For instance,
.Pa BSDmakefile
in the object directory will be favored over
.Pa Makefile
in the current directory.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl A
Make archive errors non-fatal, causing
.Nm
to just skip the remainder
or all of the archive and continue after printing a message.
.It Fl B
Try to be backwards compatible by executing a single shell per command and
by executing the commands to make the sources of a dependency line in sequence.
This is turned on by default unless
.Fl j
is used.
.It Fl C Ar directory
Change to
.Ar directory
before reading the makefiles or doing anything else.
If multiple
.Fl C
options are specified, each is interpreted relative to the previous one:
.Fl C Pa / Fl C Pa etc
is equivalent to
.Fl C Pa /etc .
.It Fl D Ar variable
Define
.Ar variable
to be 1, in the global context.
.It Fl d Ar flags
Turn on debugging, and specify which portions of
.Nm
are to print debugging information.
Argument
.Ar flags
is one or more of the following:
.Bl -tag -width Ds
.It Ar A
Print all possible debugging information;
equivalent to specifying all of the debugging flags.
.It Ar a
Print debugging information about archive searching and caching.
.It Ar c
Print debugging information about conditional evaluation.
.It Ar d
Print debugging information about directory searching and caching.
.It Ar f
Print debugging information about the execution of for loops.
.It Ar "g1"
Print the input graph before making anything.
.It Ar "g2"
Print the input graph after making everything, or before exiting
on error.
.It Ar j
Print debugging information about running multiple shells.
.It Ar l
Print commands in Makefiles regardless of whether or not they are prefixed
by @ or other "quiet" flags.
Also known as "loud" behavior.
.It Ar m
Print debugging information about making targets, including modification
dates.
.It Ar s
Print debugging information about suffix-transformation rules.
.It Ar t
Print debugging information about target list maintenance.
.It Ar v
Print debugging information about variable assignment.
.El
.It Fl E Ar variable
Specify a variable whose environment value (if any) will override
macro assignments within makefiles.
.It Fl e
Specify that environment values override macro assignments within
makefiles for all variables.
.It Fl f Ar makefile
Specify a makefile to read instead of the default one.
If
.Ar makefile
is not an absolute pathname,
.Nm
will search for it as described above.
In case
.Ar makefile
is
.Sq Fl ,
standard input is read.
Multiple
.Fl f
options can be supplied,
and the makefiles will be read in that order.
Unlike the other command-line options,
.Fl f
is neither stored in
.Va .MAKEFLAGS
nor pushed down to sub-makes via
.Ev MAKEFLAGS .
See below for more details on these variables.
.It Fl I Ar directory
Specify a directory in which to search for makefiles and included makefiles.
Multiple
.Fl I
options can be specified to form a search path.
The system makefile directory (or directories, see the
.Fl m
option) is automatically appended at the tail of this path.
.It Fl i
Ignore non-zero exit of shell commands in the makefile.
Equivalent to specifying
.Sq Ic \-
before each command line in the makefile.
.It Fl j Ar max_jobs
Specify the maximum number of jobs that
.Nm
may have running at any one time.
Turns compatibility mode off, unless the
.Fl B
flag is also specified.
.It Fl k
Continue processing after errors are encountered, but only on those targets
that do not depend on the target whose creation caused the error.
.It Fl m Ar directory
Specify a directory in which to search for
the system makefile and makefiles included via the <...> style.
Multiple
.Fl m
options can be specified to form a search path.
This path will override the default system include path,
.Pa /usr/share/mk .
The system include path will always be appended to the search path used
for "..."-style inclusions and makefile searches (see the
.Fl I
option).
.Pp
If a file or directory name in the
.Fl m
argument (or the
.Ev MAKESYSPATH
environment variable) starts with the string
.Qq \&.../
then
.Nm
will search for the specified file or directory named in the remaining part
of the argument string.
The search starts with the current directory of the Makefile and then works
upward towards the root of the filesystem.
If the search is successful,
then the resulting directory replaces the
.Qq \&.../
specification in the
.Fl m
argument.
If used, this feature allows
.Nm
to easily search in the current source tree for customized sys.mk files
(e.g. by using
.Qq \&.../mk/sys.mk
as an argument).
Note that a
.Fl C
that are earlier on the command line affect where
.Fl m Qq \&.../
searches.
.It Fl n
Display the commands that would have been executed, but do not actually
execute them.
.It Fl P
Collate the output of a given job and display it only when the job finishes,
instead of mixing the output of parallel jobs together.
This option has no effect unless
.Fl j
is used too.
.It Fl p
Only print the input graph, not executing any commands.
The output is the same as
.Fl d Ar g1 .
When combined with
.Fl f Pa /dev/null ,
only the builtin rules of
.Nm
are displayed.
.It Fl Q
Be extra quiet.
For multi-job makes, this will cause file banners not to be generated.
.It Fl q
Do not execute any commands, but exit 0 if the specified targets are
up-to-date and 1, otherwise.
.It Fl r
Do not process the system makefile.
.It Fl S
Stop processing when an error is encountered.
Default behaviour.
This is needed to negate the
.Fl k
option during recursive builds.
.It Fl s
Do not echo any commands as they are executed.
Equivalent to specifying
.Sq Ic @
before each command line in the makefile.
.It Fl t
Rather than re-building a target as specified in the makefile, create it
or update its modification time to make it appear up-to-date.
.It Fl V Ar variable
Print
.Nm Ns 's
idea of the value of
.Ar variable ,
in the global context.
Do not build any targets.
Multiple instances of this option may be specified;
the variables will be printed one per line,
with a blank line for each null or undefined variable.
If
.Ar variable
contains a
.Sq Ic $
then the value will be expanded before printing.
.It Fl v
Be extra verbose.
Print any extra information.
.It Fl X
When using the
.Fl V
option to print the values of variables,
do not recursively expand the values.
.It Ar variable Ns No = Ns Ar value
Set the value of the variable
.Ar variable
to
.Ar value .
.It Fl x Ar warning_options
Specify extended warning options.
This option may be specified several times.
A
.Ar warning_option
can be prefixed with
.Dq Li no
in which case the warning is switched off.
The currently available options are:
.Bl -tag -width indent
.It Li dirsyntax
Warn if anything except blanks and comments follows an
.Ic .endif
or
.Ic .else
directive.
.El
.Pp
See also the
.Ic .WARN
special target.
.El
.Pp
There are seven different types of lines in a makefile: file dependency
specifications, shell commands, variable assignments, include statements,
conditional directives, for loops, and comments.
.Pp
In general, lines may be continued from one line to the next by ending
them with a backslash
.Pq Ql \e .
The trailing newline character and initial whitespace on the following
line are compressed into a single space.
.Sh FILE DEPENDENCY SPECIFICATIONS
Dependency lines consist of one or more targets, an operator, and zero
or more sources.
This creates a relationship where the targets
.Dq depend
on the sources
and are usually created from them.
The exact relationship between the target and the source is determined
by the operator that separates them.
The three operators are as follows:
.Bl -tag -width flag
.It Ic \&:
A target is considered out-of-date if its modification time is less than
those of any of its sources.
Sources for a target accumulate over dependency lines when this operator
is used.
The target is removed if
.Nm
is interrupted.
.It Ic \&!
Targets are always re-created, but not until all sources have been
examined and re-created as necessary.
Sources for a target accumulate over dependency lines when this operator
is used.
The target is removed if
.Nm
is interrupted.
.It Ic ::
If no sources are specified, the target is always re-created.
Otherwise, a target is considered out-of-date if any of its sources has
been modified more recently than the target.
Sources for a target do not accumulate over dependency lines when this
operator is used.
The target will not be removed if
.Nm
is interrupted.
.El
.Pp
Targets and sources may contain the shell wildcard expressions
.Ql \&? ,
.Ql * ,
.Ql []
and
.Ql {} .
The expressions
.Ql \&? ,
.Ql *
and
.Ql []
may only be used as part of the final
component of the target or source, and must be used to describe existing
files.
The expression
.Ql {}
need not necessarily be used to describe existing files.
Expansion is in directory order, not alphabetically as done in the shell.
.Sh SHELL COMMANDS
Each target may have associated with it a series of shell commands, normally
used to create the target.
Each of the commands in this script
.Em must
be preceded by a tab.
While any target may appear on a dependency line, only one of these
dependencies may be followed by a creation script, unless the
.Sq Ic ::
operator is used.
.Pp
If the first characters of the command line are
.Sq Ic @ ,
.Sq Ic \- ,
and/or
.Sq Ic + ,
the command is treated specially.
A
.Sq Ic @
causes the command not to be echoed before it is executed.
A
.Sq Ic \-
causes any non-zero exit status of the command line to be ignored.
A
.Sq Ic +
causes the command to be executed even if
.Fl n
is specified on the command line.
.Sh VARIABLE ASSIGNMENTS
Variables in
.Nm
are much like variables in the shell, and, by tradition,
consist of all upper-case letters.
The five operators that can be used to assign values to variables are as
follows:
.Bl -tag -width Ds
.It Ic =
Assign the value to the variable.
Any previous value is overridden.
.It Ic +=
Append the value to the current value of the variable.
.It Ic ?=
Assign the value to the variable if it is not already defined.
.It Ic :=
Assign with expansion, i.e., expand the value before assigning it
to the variable.
Normally, expansion is not done until the variable is referenced.
.It Ic !=
Expand the value and pass it to the shell for execution and assign
the result to the variable.
Any newlines in the result are replaced with spaces.
.El
.Pp
Any whitespace before the assigned
.Ar value
is removed; if the value is being appended, a single space is inserted
between the previous contents of the variable and the appended value.
.Pp
Variables are expanded by surrounding the variable name with either
curly braces
.Pq Ql {}
or parentheses
.Pq Ql ()
and preceding it with
a dollar sign
.Pq Ql $ .
If the variable name contains only a single letter, the surrounding
braces or parentheses are not required.
This shorter form is not recommended.
.Pp
Variable substitution occurs at two distinct times, depending on where
the variable is being used.
Variables in dependency lines are expanded as the line is read.
Variables in shell commands are expanded when the shell command is
executed.
.Pp
The four different classes of variables (in order of increasing precedence)
are:
.Bl -tag -width Ds
.It Environment variables
Variables defined as part of
.Nm Ns 's
environment.
.It Global variables
Variables defined in the makefile or in included makefiles.
.It Command line variables
Variables defined as part of the command line and variables
obtained from the
.Ev MAKEFLAGS
environment variable or the
.Ic .MAKEFLAGS
target.
.It Local variables
Variables that are defined specific to a certain target.
.El
.Pp
If the name of an environment variable appears in a makefile
on the left-hand side of an assignment,
a global variable with the same name is created, and the latter
shadows the former as per their relative precedences.
The environment is not changed in this case, and the change
is not exported to programs executed by
.Nm .
However, a command-line variable actually replaces
the environment variable of the same name if the latter exists,
which is visible to child programs.
.Pp
There are seven local variables in
.Nm :
.Bl -tag -width ".ARCHIVE"
.It Va .ALLSRC
The list of all sources for this target; also known as
.Sq Va > .
.It Va .ARCHIVE
The name of the archive file; also known as
.Sq Va \&! .
.It Va .IMPSRC
The name/path of the source from which the target is to be transformed
(the
.Dq implied
source); also known as
.Sq Va < .
.It Va .MEMBER
The name of the archive member; also known as
.Sq Va % .
.It Va .OODATE
The list of sources for this target that were deemed out-of-date; also
known as
.Sq Va \&? .
.It Va .PREFIX
The file prefix of the file, containing only the file portion, no suffix
or preceding directory components; also known as
.Sq Va * .
.It Va .TARGET
The name of the target; also known as
.Sq Va @ .
.El
.Pp
The shorter forms
.Sq Va @ ,
.Sq Va \&! ,
.Sq Va < ,
.Sq Va % ,
.Sq Va \&? ,
.Sq Va > ,
and
.Sq Va *
are permitted for backward
compatibility and are not recommended.
The six variables
.Sq Va @F ,
.Sq Va @D ,
.Sq Va <F ,
.Sq Va <D ,
.Sq Va *F ,
and
.Sq Va *D
are
permitted for compatibility with
.At V
makefiles and are not recommended.
.Pp
Four of the local variables may be used in sources on dependency lines
because they expand to the proper value for each target on the line.
These variables are
.Va .TARGET ,
.Va .PREFIX ,
.Va .ARCHIVE ,
and
.Va .MEMBER .
.Pp
In addition,
.Nm
sets or knows about the following internal variables or environment
variables:
.Bl -tag -width ".Va .MAKEFILE_LIST"
.It Va $
A single dollar sign
.Ql $ ,
i.e.\&
.Ql $$
expands to a single dollar
sign.
.It Va MAKE
The name that
.Nm
was executed with
.Pq Va argv Ns Op 0 .
.It Va .CURDIR
A path to the directory where
.Nm
was executed.
The
.Nm
utility sets
.Va .CURDIR
to the canonical path given by
.Xr getcwd 3 .
.It Va .OBJDIR
A path to the directory where the targets are built.
At startup,
.Nm
searches for an alternate directory to place target files.
It will attempt to change into this special directory
and will search this directory for makefiles
not found in the current directory.
The following directories are tried in order:
.Pp
.Bl -enum -compact
.It
${MAKEOBJDIRPREFIX}/`pwd -P`
.It
${MAKEOBJDIR}
.It
obj.${MACHINE}
.It
obj
.It
/usr/obj/`pwd -P`
.El
.Pp
The first directory that
.Nm
successfully changes into is used.
If either
.Ev MAKEOBJDIRPREFIX
or
.Ev MAKEOBJDIR
is set in the environment but
.Nm
is unable to change into the corresponding directory,
then the current directory is used
without checking the remainder of the list.
If they are undefined and
.Nm
is unable to change into any of the remaining three directories,
then the current directory is used.
Note, that
.Ev MAKEOBJDIRPREFIX
and
.Ev MAKEOBJDIR
must be environment variables and should not be set on
.Nm Ns 's
command line.
.Pp
The
.Nm
utility sets
.Va .OBJDIR
to the canonical path given by
.Xr getcwd 3 .
.It Va .MAKEFILE_LIST
As
.Nm
reads various makefiles, including the default files and any
obtained from the command line and
.Ic .include
and
.Ic .sinclude
directives, their names will be automatically appended to the
.Va .MAKEFILE_LIST
variable.
They are added right before
.Nm
begins to parse them, so that the name of the current makefile is the
last word in this variable.
.It Ev MAKEFLAGS
The environment variable
.Ev MAKEFLAGS
may initially contain anything that
may be specified on
.Nm Ns 's
command line,
including
.Fl f
option(s).
After processing, its contents are stored in the
.Va .MAKEFLAGS
global variable, although any
.Fl f
options are omitted.
Then all options and variable assignments specified on
.Nm Ns 's
command line, except for
.Fl f ,
are appended to the
.Va .MAKEFLAGS
variable.
.Pp
Whenever
.Nm
executes a program, it sets
.Ev MAKEFLAGS
in the program's environment to the current value of the
.Va .MAKEFLAGS
global variable.
Thus, if
.Ev MAKEFLAGS
in
.Nm Ns 's
environment contains any
.Fl f
options, they will not be pushed down to child programs automatically.
The
.Nm
utility effectively filters out
.Fl f
options from the environment and command line although it
passes the rest of its options down to sub-makes via
.Ev MAKEFLAGS
by default.
.Pp
When passing macro definitions and flag arguments in the
.Ev MAKEFLAGS
environment variable,
space and tab characters are quoted by preceding them with a backslash.
When reading the
.Ev MAKEFLAGS
variable from the environment,
all sequences of a backslash and one of space or tab
are replaced just with their second character
without causing a word break.
Any other occurrences of a backslash are retained.
Groups of unquoted space, tab and newline characters cause word
breaking.
.It Va .MAKEFLAGS
Initially, this global variable contains
.Nm Ns 's
current run-time options from the environment
and command line as described above, under
.Ev MAKEFLAGS .
By modifying the contents of the
.Va .MAKEFLAGS
global variable, the makefile can alter the contents of the
.Ev MAKEFLAGS
environment variable made available for all programs which
.Nm
executes.
This includes adding
.Fl f
option(s).
The current value of
.Va .MAKEFLAGS
is just copied verbatim to
.Ev MAKEFLAGS
in the environment of child programs.
.Pp
Note that any options entered to
.Va .MAKEFLAGS
neither affect the current instance of
.Nm
nor show up in its own copy of
.Ev MAKEFLAGS
instantly.
However, they do show up in the
.Ev MAKEFLAGS
environment variable of programs executed by
.Nm .
On the other hand, a direct assignment to
.Ev MAKEFLAGS
neither affects the current instance of
.Nm
nor is passed down to
.Nm Ns 's
children.
Compare with the
.Ic .MAKEFLAGS
special target below.
.It Va MFLAGS
This variable is provided for backward compatibility and
contains all the options from the
.Ev MAKEFLAGS
environment variable plus any options specified on
.Nm Ns 's
command line.
.It Va .MAKE.PID
The process-id of
.Nm .
.It Va .MAKE.PPID
The parent process-id of
.Nm .
.It Va .MAKE.JOB.PREFIX
If
.Nm
is run with
.Fl j Fl v
then output for each target is prefixed with a token
.Ql --- target ---
the first part of which can be controlled via
.Va .MAKE.JOB.PREFIX .
.br
For example:
.Li .MAKE.JOB.PREFIX=${.newline}---${MAKE:T}[${.MAKE.PID}]
would produce tokens like
.Ql ---make[1234] target ---
or
.Li .MAKE.JOB.PREFIX=---pid[${.MAKE.PID}],ppid[${.MAKE.PPID}]
would produce tokens like
.Ql ---pid[56789],ppid[1234] target ---
making it easier to track the degree of parallelism being achieved.
.It Va .TARGETS
List of targets
.Nm
is currently building.
.It Va .INCLUDES
See
.Ic .INCLUDES
special target.
.It Va .LIBS
See
.Ic .LIBS
special target.
.It Va MACHINE
Name of the machine architecture
.Nm
is running on, obtained from the
.Ev MACHINE
environment variable, or through
.Xr uname 3
if not defined.
.It Va MACHINE_ARCH
Name of the machine architecture
.Nm
was compiled for, defined at compilation time.
.It Va VPATH
Makefiles may assign a colon-delimited list of directories to
.Va VPATH .
These directories will be searched for source files by
.Nm
after it has finished parsing all input makefiles.
.El
.Ss Variable Modifiers
Variable expansion may be modified to select or modify each word of the
variable (where a
.Dq word
is whitespace-delimited sequence of characters).
The general format of a variable expansion is as follows:
.Pp
.Dl {variable[:modifier[:...]]}
.Pp
Each modifier begins with a colon and one of the following
special characters.
The colon may be escaped with a backslash
.Pq Ql \e .
.Bl -tag -width Cm
.Sm off
.It Cm :C No / Ar pattern Xo
.No / Ar replacement
.No / Op Cm 1g
.Xc
.Sm on
Modify each word of the value,
substituting every match of the extended regular expression
.Ar pattern
(see
.Xr re_format 7 )
with the
.Xr ed 1 Ns \-style
.Ar replacement
string.
Normally, the first occurrence of the pattern in
each word of the value is changed.
The
.Ql 1
modifier causes the substitution to apply to at most one word; the
.Ql g
modifier causes the substitution to apply to as many instances of the
search pattern as occur in the word or words it is found in.
Note that
.Ql 1
and
.Ql g
are orthogonal; the former specifies whether multiple words are
potentially affected, the latter whether multiple substitutions can
potentially occur within each affected word.
.It Cm :E
Replaces each word in the variable with its suffix.
.It Cm :H
Replaces each word in the variable with everything but the last component.
.It Cm :L
Converts variable to lower-case letters.
(deprecated)
.It Cm :M Ns Ar pattern
Select only those words that match the rest of the modifier.
The standard shell wildcard characters
.Pf ( Ql * ,
.Ql \&? ,
and
.Ql [] )
may
be used.
The wildcard characters may be escaped with a backslash
.Pq Ql \e .
.It Cm :N Ns Ar pattern
This is identical to
.Cm :M ,
but selects all words which do not match
the rest of the modifier.
.It Cm :O
Order every word in the variable alphabetically.
.It Cm :Q
Quotes every shell meta-character in the variable, so that it can be passed
safely through recursive invocations of
.Nm .
.It Cm :R
Replaces each word in the variable with everything but its suffix.
.Sm off
.It Cm :S No / Ar old_string Xo
.No / Ar new_string
.No / Op Cm g
.Xc
.Sm on
Modify the first occurrence of
.Ar old_string
in each word of the variable's value, replacing it with
.Ar new_string .
If a
.Ql g
is appended to the last slash of the pattern, all occurrences
in each word are replaced.
If
.Ar old_string
begins with a caret
.Pq Ql ^ ,
.Ar old_string
is anchored at the beginning of each word.
If
.Ar old_string
ends with a dollar sign
.Pq Ql $ ,
it is anchored at the end of each word.
Inside
.Ar new_string ,
an ampersand
.Pq Ql &
is replaced by
.Ar old_string .
Any character may be used as a delimiter for the parts of the modifier
string.
The anchoring, ampersand, and delimiter characters may be escaped with a
backslash
.Pq Ql \e .
.Pp
Variable expansion occurs in the normal fashion inside both
.Ar old_string
and
.Ar new_string
with the single exception that a backslash is used to prevent the expansion
of a dollar sign
.Pq Ql $ ,
not a preceding dollar sign as is usual.
.It Ar :old_string=new_string
This is the
.At V
style variable substitution.
It must be the last modifier specified.
If
.Ar old_string
or
.Ar new_string
do not contain the pattern matching character
.Ar %
then it is assumed that they are
anchored at the end of each word, so only suffixes or entire
words may be replaced.
Otherwise
.Ar %
is the substring of
.Ar old_string
to be replaced in
.Ar new_string .
.It Cm :T
Replaces each word in the variable with its last component.
.It Cm :tl
Converts variable to lower-case letters.
.It Cm :tu
Converts variable to upper-case letters.
.It Cm :U
Converts variable to upper-case letters.
(deprecated)
.It Cm :u
Remove adjacent duplicate words (like
.Xr uniq 1 ) .
.El
.Sh DIRECTIVES, CONDITIONALS, AND FOR LOOPS
Directives, conditionals, and for loops reminiscent
of the C programming language are provided in
.Nm .
All such structures are identified by a line beginning with a single
dot
.Pq Ql \&.
character.
The following directives are supported:
.Bl -tag -width Ds
.It Ic .include Ar <file>
.It Ic .include Ar \*qfile\*q
Include the specified makefile.
Variables between the angle brackets
or double quotes are expanded to form the file name.
If angle brackets
are used, the included makefile is expected to be in the system
makefile directory.
If double quotes are used, the including
makefile's directory and any directories specified using the
.Fl I
option are searched before the system
makefile directory.
.It Ic .sinclude Ar <file>
.It Ic .sinclude Ar \*qfile\*q
Like
.Ic .include ,
but silently ignored if the file cannot be found and opened.
.It Ic .undef Ar variable
Un-define the specified global variable.
Only global variables may be un-defined.
.It Ic .error Ar message
Terminate processing of the makefile immediately.
The filename of the
makefile, the line on which the error was encountered and the specified
message are printed to the standard error output and
.Nm
terminates with exit code 1.
Variables in the message are expanded.
.It Ic .warning Ar message
Emit a warning message.
The filename of the makefile,
the line on which the warning was encountered,
and the specified message are printed to the standard error output.
Variables in the message are expanded.
.El
.Pp
Conditionals are used to determine which parts of the Makefile
to process.
They are used similarly to the conditionals supported
by the C pre-processor.
The following conditionals are supported:
.Bl -tag -width Ds
.It Xo
.Ic .if
.Oo \&! Oc Ns Ar expression
.Op Ar operator expression ...
.Xc
Test the value of an expression.
.It Xo
.Ic .ifdef
.Oo \&! Oc Ns Ar variable
.Op Ar operator variable ...
.Xc
Test the value of a variable.
.It Xo
.Ic .ifndef
.Oo \&! Oc Ns Ar variable
.Op Ar operator variable ...
.Xc
Test the value of a variable.
.It Xo
.Ic .ifmake
.Oo \&! Oc Ns Ar target
.Op Ar operator target ...
.Xc
Test the target being built.
.It Xo
.Ic .ifnmake
.Oo \&! Oc Ns Ar target
.Op Ar operator target ...
.Xc
Test the target being built.
.It Ic .else
Reverse the sense of the last conditional.
.It Xo
.Ic .elif
.Oo \&! Oc Ns Ar expression
.Op Ar operator expression ...
.Xc
A combination of
.Ic .else
followed by
.Ic .if .
.It Xo
.Ic .elifdef
.Oo \&! Oc Ns Ar variable
.Op Ar operator variable ...
.Xc
A combination of
.Ic .else
followed by
.Ic .ifdef .
.It Xo
.Ic .elifndef
.Oo \&! Oc Ns Ar variable
.Op Ar operator variable ...
.Xc
A combination of
.Ic .else
followed by
.Ic .ifndef .
.It Xo
.Ic .elifmake
.Oo \&! Oc Ns Ar target
.Op Ar operator target ...
.Xc
A combination of
.Ic .else
followed by
.Ic .ifmake .
.It Xo
.Ic .elifnmake
.Oo \&! Oc Ns Ar target
.Op Ar operator target ...
.Xc
A combination of
.Ic .else
followed by
.Ic .ifnmake .
.It Ic .endif
End the body of the conditional.
.El
.Pp
The
.Ar operator
may be any one of the following:
.Bl -tag -width "Cm XX"
.It Cm ||
Logical
.Tn OR
.It Cm &&
Logical
.Tn AND ;
of higher precedence than
.Sq Ic || .
.El
.Pp
As in C,
.Nm
will only evaluate a conditional as far as is necessary to determine
its value.
Parentheses may be used to change the order of evaluation.
The boolean operator
.Sq Ic !\&
may be used to logically negate an entire
conditional.
It is of higher precedence than
.Sq Ic && .
.Pp
The value of
.Ar expression
may be any of the following:
.Bl -tag -width Ic
.It Ic defined
Takes a variable name as an argument and evaluates to true if the variable
has been defined.
.It Ic make
Takes a target name as an argument and evaluates to true if the target
was specified as part of
.Nm Ns 's
command line or was declared the default target (either implicitly or
explicitly, see
.Va .MAIN )
before the line containing the conditional.
.It Ic empty
Takes a variable, with possible modifiers, and evaluates to true if
the expansion of the variable would result in an empty string.
.It Ic exists
Takes a file name as an argument and evaluates to true if the file exists.
The file is searched for on the system search path (see
.Va .PATH ) .
.It Ic target
Takes a target name as an argument and evaluates to true if the target
has been defined.
.El
.Pp
An
.Ar expression
may also be a numeric or string comparison:
in this case, the left-hand side
.Ar must be
a variable expansion, whereas the right-hand side can be a
constant or a variable expansion.
Variable expansion is performed on both sides, after which the resulting
values are compared.
A value is interpreted as hexadecimal if it is
preceded by 0x, otherwise it is decimal; octal numbers are not supported.
.Pp
String comparison can only use the
.Sq Ic ==
or
.Sq Ic !=
operators, whereas numeric values (both integer and floating point)
can also be compared using the
.Sq Ic > ,
.Sq Ic >= ,
.Sq Ic <
and
.Sq Ic <=
operators.
.Pp
If no relational operator (and right-hand value) are given, an implicit
.Sq Ic != 0
is used.
However be very careful in using this feature especially
when the left-hand side variable expansion returns a string.
.Pp
When
.Nm
is evaluating one of these conditional expressions, and it encounters
a word it does not recognize, either the
.Dq make
or
.Dq defined
expression is applied to it, depending on the form of the conditional.
If the form is
.Ic .if ,
.Ic .ifdef
or
.Ic .ifndef ,
the
.Dq defined
expression is applied.
Similarly, if the form is
.Ic .ifmake
or
.Ic .ifnmake ,
the
.Dq make
expression is applied.
.Pp
If the conditional evaluates to true the parsing of the makefile continues
as before.
If it evaluates to false, the following lines are skipped.
In both cases this continues until a
.Ic .else
or
.Ic .endif
is found.
.Pp
For loops are typically used to apply a set of rules to a list of files.
The syntax of a for loop is:
.Pp
.Bl -tag -width indent -compact
.It Ic .for Ar variable Ic in Ar expression
.It <make-rules>
.It Ic .endfor
.El
.Pp
After the for
.Ar expression
is evaluated, it is split into words.
The
iteration
.Ar variable
is successively set to each word, and substituted in the
.Ic make-rules
inside the body of the for loop.
.Sh COMMENTS
Comments begin with a hash
.Pq Ql #
character, anywhere but in a shell
command line, and continue to the end of the line.
.Sh SPECIAL SOURCES
.Bl -tag -width Ic
.It Ic .IGNORE
Ignore any errors from the commands associated with this target, exactly
as if they all were preceded by a dash
.Pq Ql \- .
.It Ic .MAKE
Execute the commands associated with this target even if the
.Fl n
or
.Fl t
options were specified.
Normally used to mark recursive
.Nm Ns 's .
.It Ic .NOTMAIN
Normally
.Nm
selects the first target it encounters as the default target to be built
if no target was specified.
This source prevents this target from being selected.
.It Ic .OPTIONAL
If a target is marked with this attribute and
.Nm
cannot figure out how to create it, it will ignore this fact and assume
the file is not needed or already exists.
.It Ic .PRECIOUS
When
.Nm
is interrupted, it removes any partially made targets.
This source prevents the target from being removed.
.It Ic .SILENT
Do not echo any of the commands associated with this target, exactly
as if they all were preceded by an at sign
.Pq Ql @ .
.It Ic .USE
Turn the target into
.Nm Ns 's
version of a macro.
When the target is used as a source for another target, the other target
acquires the commands, sources, and attributes (except for
.Ic .USE )
of the
source.
If the target already has commands, the
.Ic .USE
target's commands are appended
to them.
.It Ic .WAIT
If special
.Ic .WAIT
source appears in a dependency line, the sources that precede it are
made before the sources that succeed it in the line.
Loops are not being
detected and targets that form loops will be silently ignored.
.El
.Sh SPECIAL TARGETS
Special targets may not be included with other targets, i.e., they must be
the only target specified.
.Bl -tag -width Ic
.It Ic .BEGIN
Any command lines attached to this target are executed before anything
else is done.
.It Ic .DEFAULT
This is sort of a
.Ic .USE
rule for any target (that was used only as a
source) that
.Nm
cannot figure out any other way to create.
Only the shell script is used.
The
.Ic .IMPSRC
variable of a target that inherits
.Ic .DEFAULT Ns 's
commands is set
to the target's own name.
.It Ic .END
Any command lines attached to this target are executed after everything
else is done.
.It Ic .IGNORE
Mark each of the sources with the
.Ic .IGNORE
attribute.
If no sources are specified, this is the equivalent of specifying the
.Fl i
option.
.It Ic .INCLUDES
A list of suffixes that indicate files that can be included in a source
file.
The suffix must have already been declared with
.Ic .SUFFIXES ;
any suffix so declared will have the directories on its search path (see
.Ic .PATH )
placed in the
.Va .INCLUDES
special variable, each preceded by a
.Fl I
flag.
.It Ic .INTERRUPT
If
.Nm
is interrupted, the commands for this target will be executed.
.It Ic .LIBS
This does for libraries what
.Ic .INCLUDES
does for include files, except that the flag used is
.Fl L .
.It Ic .MAIN
If no target is specified when
.Nm
is invoked, this target will be built.
This is always set, either
explicitly, or implicitly when
.Nm
selects the default target, to give the user a way to refer to the default
target on the command line.
.It Ic .MAKEFILEDEPS
Enable the
.Dq Remaking Makefiles
functionality, as explained in the
.Sx REMAKING MAKEFILES
section below.
.It Ic .MAKEFLAGS
This target provides a way to specify flags for
.Nm
when the makefile is used.
The flags are as if typed to the shell, though the
.Fl f
option will have
no effect.
Flags (except for
.Fl f )
and variable assignments specified as the source
for this target are also appended to the
.Va .MAKEFLAGS
internal variable.
Please note the difference between this target and the
.Va .MAKEFLAGS
internal variable: specifying an option or variable
assignment as the source for this target will affect
.Em both
the current makefile and all processes that
.Nm
executes.
.It Ic .MFLAGS
Same as above, for backward compatibility.
.\" XXX: NOT YET!!!!
.\" .It Ic .NOTPARALLEL
.\" The named targets are executed in non parallel mode. If no targets are
.\" specified, then all targets are executed in non parallel mode.
.It Ic .NOTPARALLEL
Disable parallel mode.
.It Ic .NO_PARALLEL
Same as above, for compatibility with other
.Nm pmake
variants.
.It Ic .ORDER
The named targets are made in sequence.
.\" XXX: NOT YET!!!!
.\" .It Ic .PARALLEL
.\" The named targets are executed in parallel mode. If no targets are
.\" specified, then all targets are executed in parallel mode.
.It Ic .PATH
The sources are directories which are to be searched for files not
found in the current directory.
If no sources are specified, any previously specified directories are
deleted.
Where possible, use of
.Ic .PATH
is preferred over use of the
.Va VPATH
variable.
.It Ic .PATH\fIsuffix\fR
The sources are directories which are to be searched for suffixed files
not found in the current directory.
The
.Nm
utility
first searches the suffixed search path, before reverting to the default
path if the file is not found there.
This form is required for
.Ic .LIBS
and
.Ic .INCLUDES
to work.
.It Ic .PHONY
Apply the
.Ic .PHONY
attribute to any specified sources.
Targets with this attribute are always
considered to be out of date.
.It Ic .POSIX
Adjust
.Nm Ap s
behavior to match the applicable
.Tn POSIX
specifications.
(Note this disables the
.Dq Remaking Makefiles
feature.)
.It Ic .PRECIOUS
Apply the
.Ic .PRECIOUS
attribute to any specified sources.
If no sources are specified, the
.Ic .PRECIOUS
attribute is applied to every
target in the file.
.It Ic .SHELL
Select another shell.
The sources of this target have the format
.Ar key Ns = Ns Ar value .
The
.Ar key
is one of:
.Bl -tag -width ".Va hasErrCtl"
.It Va path
Specify the path to the new shell.
.It Va name
Specify the name of the new shell.
This may be either one of the three builtin shells (see below) or any
other name.
.It Va quiet
Specify the shell command to turn echoing off.
.It Va echo
Specify the shell command to turn echoing on.
.It Va filter
Usually shells print the echo off command before turning echoing off.
This is the exact string that will be printed by the shell and is used
to filter the shell output to remove the echo off command.
.It Va echoFlag
The shell option that turns echoing on.
.It Va errFlag
The shell option to turn on error checking.
If error checking is on, the shell should exit if a command returns
a non-zero status.
.It Va hasErrCtl
True if the shell has error control.
.It Va check
If
.Va hasErrCtl
is true then this is the shell command to turn error checking on.
If
.Va hasErrCtl
is false then this is a command template to echo commands for which error
checking is disabled.
The template must contain a
.Ql %s .
.It Va ignore
If
.Va hasErrCtl
is true, this is the shell command to turn error checking off.
If
.Va hasErrCtl
is false, this is a command template to execute a command so that errors
are ignored.
The template must contain a
.Ql %s .
.It Va meta
This is a string of meta characters of the shell.
.It Va builtins
This is a string holding all the shell's builtin commands separated by blanks.
The
.Va meta
and
.Va builtins
strings are used in compat mode.
When a command line contains neither a meta
character nor starts with a shell builtin, it is executed directly without
invoking a shell.
When one of these strings (or both) is empty all commands are executed
through a shell.
.It Va unsetenv
If true, remove the
.Ev ENV
environment variable before executing any command.
This is useful for the Korn-shell
.Pq Nm ksh .
.El
.Pp
Values that are strings must be surrounded by double quotes.
Boolean values are specified as
.Ql T
or
.Ql Y
(in either case) to mean true.
Any other value is taken to mean false.
.Pp
There are several uses of the
.Ic .SHELL
target:
.Bl -bullet
.It
Selecting one of the builtin shells.
This is done by just specifying the name of the shell with the
.Va name
keyword.
It is also possible to modify the parameters of the builtin shell by just
specifying other keywords (except for
.Va path ) .
.It
Using another executable for one of the builtin shells.
This is done by specifying the path to the executable with the
.Va path
keyword.
If the last component is the same as the name of the builtin shell, no
name needs to be specified; if it is different, the name must be given:
.Bd -literal -offset indent
\&.SHELL: path="/usr/local/bin/sh"
.Ed
.Pp
selects the builtin shell
.Dq Li sh
but will execute it from
.Pa /usr/local/bin/sh .
Like in the previous case, it is possible to modify parameters of the builtin
shell by just specifying them.
.It
Using an entirely different shell.
This is done by specifying all keywords.
.El
.Pp
The builtin shells are
.Dq Li sh ,
.Dq Li csh
and
.Dq Li ksh .
Because
.Fx
has no
.Nm ksh
in
.Pa /bin ,
it is unwise to specify
.Va name Ns = Ns Qq Li ksh
without also specifying a path.
.It Ic .SILENT
Apply the
.Ic .SILENT
attribute to any specified sources.
If no sources are specified, the
.Ic .SILENT
attribute is applied to every
command in the file.
.It Ic .SUFFIXES
Each source specifies a suffix to
.Nm .
If no sources are specified, any previous specified suffixes are deleted.
.It Ic .WARN
Each source specifies a warning flag as previously described for the
.Fl x
command line option.
Warning flags specified on the command line take precedence over flags
specified in the makefile.
Also, command line warning flags are pushed to sub-makes through the
.Ev MAKEFLAGS
environment variables so that a warning flag specified on the command
line will influence all sub-makes.
Several flags can be specified on a single
.Ic .WARN
target by separating them with blanks.
.El
.Sh REMAKING MAKEFILES
If the special target
.Ic .MAKEFILEDEPS
exists in the Makefile,
.Nm
enables the
.Dq Remaking Makefiles
feature.
After reading Makefile and all the files that are included using
.Ic .include
or
.Ic .sinclude
directives (source Makefiles)
.Nm
considers each source Makefile as a target and tries to rebuild it.
Both explicit and implicit rules are checked and all source Makefiles
are updated if necessary. If any of the source Makefiles were rebuilt,
.Nm
restarts from clean state.
.Pp
To prevent infinite loops the following source Makefile targets are ignored:
.Bl -bullet
.It
.Ic ::
targets that have no prerequisites
.It
.Ic \&!
targets
.It
targets that have
.Ic .PHONY
or
.Ic .EXEC
attributes
.It
targets without prerequisites and without commands
.El
.Pp
When remaking a source Makefile options
.Ic -t
(touch target),
.Ic -q
(query mode), and
.Ic -n
(no exec) do not take effect, unless source Makefile is specified
explicitly as a target in
.Nm
command line.
.Pp
Additionally, system makefiles and
.Ic .depend
are not considered as Makefiles that can be rebuilt.
.Sh ENVIRONMENT
The
.Nm
utility uses the following environment variables, if they exist:
.Ev MACHINE ,
.Ev MAKE ,
.Ev MAKEFLAGS ,
.Ev MAKEOBJDIR ,
.Ev MAKEOBJDIRPREFIX ,
and
.Ev MAKESYSPATH .
.Sh FILES
.Bl -tag -width /usr/share/doc/psd/12.make -compact
.It Pa .depend
list of dependencies
.It Pa Makefile
list of dependencies
.It Pa makefile
list of dependencies
.It Pa obj
object directory
.It Pa sys.mk
system makefile
.It Pa /usr/share/mk
default system makefile directory
.It Pa /usr/share/doc/psd/12.make
PMake tutorial
.It Pa /usr/obj
default
.Ev MAKEOBJDIRPREFIX
directory.
.It Pa /etc/make.conf
default path to
.Xr make.conf 5
.El
.Sh EXAMPLES
List all included makefiles in order visited:
.Pp
.Dl "make -V .MAKEFILE_LIST | tr \e\  \e\en"
.Sh COMPATIBILITY
Older versions of
.Nm
used
.Ev MAKE
instead of
.Ev MAKEFLAGS .
This was removed for
.Tn POSIX
compatibility.
The internal variable
.Va MAKE
is set to the same value as
.Va .MAKE ;
support for this may be removed in the future.
.Pp
The use of the
.Cm :L
and
.Cm :U
modifiers are deprecated
in
.Fx 10.0
and the more portable (among Pmake decedents)
.Cm :tl
and
.Cm :tu
should be used instead.
.Pp
Most of the more esoteric features of
.Nm
should probably be avoided for greater compatibility.
.Sh SEE ALSO
.Xr mkdep 1 ,
.Xr make.conf 5
.Rs
.%T "PMake - A Tutorial"
.Re
in
.Pa /usr/share/doc/psd/12.make
.Sh HISTORY
A
.Nm
command appeared in PWB UNIX.
.Sh BUGS
The determination of
.Va .OBJDIR
is contorted to the point of absurdity.
.Pp
In the presence of several
.Ic .MAIN
special targets,
.Nm
silently ignores all but the first.
.Pp
.Va .TARGETS
is not set to the default target when
.Nm
is invoked without a target name and no
.Ic .MAIN
special target exists.
.Pp
The evaluation of
.Ar expression
in a test is very simple-minded.
Currently, the only form that works is
.Ql .if ${VAR} op something .
For instance, you should write tests as
.Ql .if ${VAR} == "string"
not the other way around, which would give you an error.
.Pp
For loops are expanded before tests, so a fragment such as:
.Bd -literal -offset indent
\&.for ARCH in ${SHARED_ARCHS}
\&.if ${ARCH} == ${MACHINE}
     ...
\&.endif
\&.endfor
.Ed
.Pp
will not work, and should be rewritten as:
.Bd -literal -offset indent
\&.for ARCH in ${SHARED_ARCHS}
\&.if ${MACHINE} == ${ARCH}
     ...
\&.endif
\&.endfor
.Ed
.Pp
The parsing code is broken with respect to handling a semicolon
after a colon, so a fragment like this will fail:
.Bd -literal -offset indent
HDRS=   foo.h bar.h

all:
\&.for h in ${HDRS:S;^;${.CURDIR}/;}
     ...
\&.endfor
.Ed
.Pp
A trailing backslash in a variable value defined on the command line causes
the delimiting space in the
.Ev MAKEFLAGS
environment variable to be preceded by that backslash.
That causes a submake to not treat that space as a word delimiter.
Fixing this requires a larger rewrite of the code handling command line
macros and assignments to
.Va .MAKEFLAGS .