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MAKE(1)                     General Commands Manual                    MAKE(1)

     make - maintain program dependencies

     make [-BeikNnqrSstWwX] [-C directory] [-D variable] [-d flags]
          [-f makefile] [-I directory] [-J private] [-j max_jobs]
          [-m directory] [-T file] [-V variable] [-v variable]
          [variable=value] [target ...]

     make is a program designed to simplify the maintenance of other programs.
     Its input is a list of specifications as to the files upon which programs
     and other files depend.  If no -f makefile option is given, make tries to
     open `makefile' then `Makefile' in order to find the specifications.  If
     the file `.depend' exists, it is read (see mkdep(1)).

     This manual page is intended as a reference document only.  For a more
     thorough description of make and makefiles, please refer to PMake - A
     Tutorial (from 1993).

     make prepends the contents of the MAKEFLAGS environment variable to the
     command line arguments before parsing them.

     The options are as follows:

     -B      Try to be backwards compatible by executing a single shell per
             command and by making the sources of a dependency line in

     -C directory
             Change to directory before reading the makefiles or doing
             anything else.  If multiple -C options are specified, each is
             interpreted relative to the previous one: -C / -C etc is
             equivalent to -C /etc.

     -D variable
             Define variable to be 1, in the global scope.

     -d [-]flags
             Turn on debugging, and specify which portions of make are to
             print debugging information.  Unless the flags are preceded by
             `-', they are added to the MAKEFLAGS environment variable and are
             passed on to any child make processes.  By default, debugging
             information is printed to standard error, but this can be changed
             using the F debugging flag.  The debugging output is always
             unbuffered; in addition, if debugging is enabled but debugging
             output is not directed to standard output, the standard output is
             line buffered.  The available flags are:

             A       Print all possible debugging information; equivalent to
                     specifying all of the debugging flags.

             a       Print debugging information about archive searching and

             C       Print debugging information about the current working

             c       Print debugging information about conditional evaluation.

             d       Print debugging information about directory searching and

             e       Print debugging information about failed commands and

                     Specify where debugging output is written.  This must be
                     the last flag, because it consumes the remainder of the
                     argument.  If the character immediately after the F flag
                     is `+', the file is opened in append mode; otherwise the
                     file is overwritten.  If the file name is `stdout' or
                     `stderr', debugging output is written to the standard
                     output or standard error output file descriptors
                     respectively (and the `+' option has no effect).
                     Otherwise, the output is written to the named file.  If
                     the file name ends with `.%d', the `%d' is replaced by
                     the pid.

             f       Print debugging information about loop evaluation.

             g1      Print the input graph before making anything.

             g2      Print the input graph after making everything, or before
                     exiting on error.

             g3      Print the input graph before exiting on error.

             h       Print debugging information about hash table operations.

             j       Print debugging information about running multiple

             L       Turn on lint checks.  This throws errors for variable
                     assignments that do not parse correctly, at the time of
                     assignment, so the file and line number are available.

             l       Print commands in Makefiles regardless of whether or not
                     they are prefixed by `@' or other "quiet" flags.  Also
                     known as "loud" behavior.

             M       Print debugging information about "meta" mode decisions
                     about targets.

             m       Print debugging information about making targets,
                     including modification dates.

             n       Don't delete the temporary command scripts created when
                     running commands.  These temporary scripts are created in
                     the directory referred to by the TMPDIR environment
                     variable, or in /tmp if TMPDIR is unset or set to the
                     empty string.  The temporary scripts are created by
                     mkstemp(3), and have names of the form makeXXXXXX.  NOTE:
                     This can create many files in TMPDIR or /tmp, so use with

             p       Print debugging information about makefile parsing.

             s       Print debugging information about suffix-transformation

             t       Print debugging information about target list

             V       Force the -V option to print raw values of variables,
                     overriding the default behavior set via

             v       Print debugging information about variable assignment and

             x       Run shell commands with -x so the actual commands are
                     printed as they are executed.

     -e      Let environment variables override global variables within

     -f makefile
             Specify a makefile to read instead of the default makefile or
             Makefile.  If makefile is `-', standard input is read.  Multiple
             makefiles may be specified, and are read in the order specified.

     -I directory
             Specify a directory in which to search for makefiles and included
             makefiles.  The system makefile directory (or directories, see
             the -m option) is automatically included as part of this list.

     -i      Ignore non-zero exit of shell commands in the makefile.
             Equivalent to specifying `-' before each command line in the

     -J private
             This option should not be specified by the user.

             When the -j option is in use in a recursive build, this option is
             passed by a make to child makes to allow all the make processes
             in the build to cooperate to avoid overloading the system.

     -j max_jobs
             Specify the maximum number of jobs that make may have running at
             any one time.  The value is saved in .MAKE.JOBS.  Turns
             compatibility mode off, unless the -B option is also specified.
             When compatibility mode is off, all commands associated with a
             target are executed in a single shell invocation as opposed to
             the traditional one shell invocation per line.  This can break
             traditional scripts which change directories on each command
             invocation and then expect to start with a fresh environment on
             the next line.  It is more efficient to correct the scripts
             rather than turn backwards compatibility on.

     -k      Continue processing after errors are encountered, but only on
             those targets that do not depend on the target whose creation
             caused the error.

     -m directory
             Specify a directory in which to search for sys.mk and makefiles
             included via the <file>-style include statement.  The -m option
             can be used multiple times to form a search path.  This path
             overrides the default system include path /usr/share/mk.
             Furthermore, the system include path is appended to the search
             path used for "file"-style include statements (see the -I

             If a directory name in the -m argument (or the MAKESYSPATH
             environment variable) starts with the string `.../', make
             searches for the specified file or directory named in the
             remaining part of the argument string.  The search starts with
             the current directory and then works upward towards the root of
             the file system.  If the search is successful, the resulting
             directory replaces the `.../' specification in the -m argument.
             This feature allows make to easily search in the current source
             tree for customized sys.mk files (e.g., by using `.../mk/sys.mk'
             as an argument).

     -n      Display the commands that would have been executed, but do not
             actually execute them unless the target depends on the .MAKE
             special source (see below) or the command is prefixed with `+'.

     -N      Display the commands that would have been executed, but do not
             actually execute any of them; useful for debugging top-level
             makefiles without descending into subdirectories.

     -q      Do not execute any commands, instead exit 0 if the specified
             targets are up to date, and 1 otherwise.

     -r      Do not use the built-in rules specified in the system makefile.

     -S      Stop processing if an error is encountered.  This is the default
             behavior and the opposite of -k.

     -s      Do not echo any commands as they are executed.  Equivalent to
             specifying `@' before each command line in the makefile.

     -T tracefile
             When used with the -j flag, append a trace record to tracefile
             for each job started and completed.

     -t      Rather than re-building a target as specified in the makefile,
             create it or update its modification time to make it appear up-

     -V variable
             Print the value of variable.  Do not build any targets.  Multiple
             instances of this option may be specified; the variables are
             printed one per line, with a blank line for each null or
             undefined variable.  The value printed is extracted from the
             global scope after all makefiles have been read.  By default, the
             raw variable contents (which may include additional unexpanded
             variable references) are shown.  If variable contains a `$', the
             value is recursively expanded to its complete resultant text
             before printing.  The expanded value is also printed if
             .MAKE.EXPAND_VARIABLES is set to true and the -dV option has not
             been used to override it.  Note that loop-local and target-local
             variables, as well as values taken temporarily by global
             variables during makefile processing, are not accessible via this
             option.  The -dv debug mode can be used to see these at the cost
             of generating substantial extraneous output.

     -v variable
             Like -V, but all printed variables are always expanded to their
             complete value.  The last occurrence of -V or -v decides whether
             all variables are expanded or not.

     -W      Treat any warnings during makefile parsing as errors.

     -w      Print entering and leaving directory messages, pre and post

     -X      Don't export variables passed on the command line to the
             environment individually.  Variables passed on the command line
             are still exported via the MAKEFLAGS environment variable.  This
             option may be useful on systems which have a small limit on the
             size of command arguments.

             Set the value of the variable variable to value.  Normally, all
             values passed on the command line are also exported to sub-makes
             in the environment.  The -X flag disables this behavior.
             Variable assignments should follow options for POSIX
             compatibility but no ordering is enforced.

     There are several different types of lines in a makefile: dependency
     specifications, shell commands, variable assignments, include statements,
     conditional directives, for loops, other directives, and comments.

     Lines may be continued from one line to the next by ending them with a
     backslash (`\').  The trailing newline character and initial whitespace
     on the following line are compressed into a single space.

     Dependency lines consist of one or more targets, an operator, and zero or
     more sources.  This creates a relationship where the targets "depend" on
     the sources and are customarily created from them.  A target is
     considered out of date if it does not exist, or if its modification time
     is less than that of any of its sources.  An out-of-date target is re-
     created, but not until all sources have been examined and themselves re-
     created as needed.  Three operators may be used:

     :     Many dependency lines may name this target but only one may have
           attached shell commands.  All sources named in all dependency lines
           are considered together, and if needed the attached shell commands
           are run to create or re-create the target.  If make is interrupted,
           the target is removed.

     !     The same, but the target is always re-created whether or not it is
           out of date.

     ::    Any dependency line may have attached shell commands, but each one
           is handled independently: its sources are considered and the
           attached shell commands are run if the target is out of date with
           respect to (only) those sources.  Thus, different groups of the
           attached shell commands may be run depending on the circumstances.
           Furthermore, unlike :, for dependency lines with no sources, the
           attached shell commands are always run.  Also unlike :, the target
           is not removed if make is interrupted.
     All dependency lines mentioning a particular target must use the same

     Targets and sources may contain the shell wildcard values `?', `*', `[]',
     and `{}'.  The values `?', `*', and `[]' may only be used as part of the
     final component of the target or source, and only match existing files.
     The value `{}' need not necessarily be used to describe existing files.
     Expansion is in directory order, not alphabetically as done in the shell.

     Each target may have associated with it one or more lines of shell
     commands, normally used to create the target.  Each of the lines in this
     script must be preceded by a tab.  (For historical reasons, spaces are
     not accepted.)  While targets can occur in many dependency lines if
     desired, by default only one of these rules may be followed by a creation
     script.  If the `::' operator is used, however, all rules may include
     scripts and the scripts are executed in the order found.

     Each line is treated as a separate shell command, unless the end of line
     is escaped with a backslash (`\'), in which case that line and the next
     are combined.  If the first characters of the command are any combination
     of `@', `+', or `-', the command is treated specially.  A `@' causes the
     command not to be echoed before it is executed.  A `+' causes the command
     to be executed even when -n is given.  This is similar to the effect of
     the .MAKE special source, except that the effect can be limited to a
     single line of a script.  A `-' in compatibility mode causes any non-zero
     exit status of the command line to be ignored.

     When make is run in jobs mode with -j max_jobs, the entire script for the
     target is fed to a single instance of the shell.  In compatibility (non-
     jobs) mode, each command is run in a separate process.  If the command
     contains any shell meta characters (`#=|^(){};&<>*?[]:$`\\n'), it is
     passed to the shell; otherwise make attempts direct execution.  If a line
     starts with `-' and the shell has ErrCtl enabled, failure of the command
     line is ignored as in compatibility mode.  Otherwise `-' affects the
     entire job; the script stops at the first command line that fails, but
     the target is not deemed to have failed.

     Makefiles should be written so that the mode of make operation does not
     change their behavior.  For example, any command which uses "cd" or
     "chdir" without the intention of changing the directory for subsequent
     commands should be put in parentheses so it executes in a subshell.  To
     force the use of a single shell, escape the line breaks so as to make the
     whole script one command.  For example:

                   @echo Building $@ in `pwd`
                   @(cd ${.CURDIR} && ${MAKE} $@)
                   @echo Back in `pwd`

                   @echo Building $@ in `pwd`; \
                   (cd ${.CURDIR} && ${MAKE} $@); \
                   echo Back in `pwd`

     Since make changes the current working directory to `.OBJDIR' before
     executing any targets, each child process starts with that as its current
     working directory.

     Variables in make behave much like macros in the C preprocessor.

     Variable assignments have the form `NAME op value', where:

     NAME    is a single-word variable name, consisting, by tradition, of all
             upper-case letters,

     op      is one of the five variable assignment operators described below,

     value   is interpreted according to the variable assignment operator.

     Whitespace around NAME, op and value is discarded.

   Variable assignment operators
     The five operators that assign values to variables are:

     =       Assign the value to the variable.  Any previous value is

     +=      Append the value to the current value of the variable, separating
             them by a single space.

     ?=      Assign the value to the variable if it is not already defined.

     :=      Assign with expansion, i.e. expand the value before assigning it
             to the variable.  Normally, expansion is not done until the
             variable is referenced.

             NOTE: References to undefined variables are not expanded.  This
             can cause problems when variable modifiers are used.

     !=      Expand the value and pass it to the shell for execution, then
             assign the output from the child's standard output to the
             variable.  Any newlines in the result are replaced with spaces.

   Expansion of variables
     In most contexts where variables are expanded, `$$' expands to a single
     dollar sign.  In other contexts (most variable modifiers, string literals
     in conditions), `\$' expands to a single dollar sign.

     References to variables have the form ${name[:modifiers]} or
     $(name[:modifiers]).  If the variable name consists of only a single
     character, the surrounding curly braces or parentheses are not required.
     This shorter form is not recommended.

     If the variable name contains a dollar, the name itself is expanded
     first.  This allows almost arbitrary variable names, however names
     containing dollar, braces, parentheses or whitespace are really best

     If the result of expanding a nested variable expression contains a dollar
     sign (`$'), the string is subject to further expansion.

     Variable substitution occurs at four distinct times, depending on where
     the variable is being used.

     1.   Variables in dependency lines are expanded as the line is read.

     2.   Variables in conditionals are expanded individually, but only as far
          as necessary to determine the result of the conditional.

     3.   Variables in shell commands are expanded when the shell command is

     4.   .for loop index variables are expanded on each loop iteration.  Note
          that other variables are not expanded when composing the body of a
          loop, so the following example code:

                .for i in 1 2 3
                a+=     ${i}
                j=      ${i}
                b+=     ${j}

                        @echo ${a}
                        @echo ${b}


                1 2 3
                3 3 3

          Because while a contains `${:U1} ${:U2} ${:U3}' after the loop is
          executed, b contains `${j} ${j} ${j}' which expands to `3 3 3' since
          after the loop completes j contains `${:U3}'.

   Variable classes
     The four different classes of variables (in order of increasing
     precedence) are:

     Environment variables
             Variables defined as part of make's environment.

     Global variables
             Variables defined in the makefile or in included makefiles.

     Command line variables
             Variables defined as part of the command line.

     Local variables
             Variables that are defined specific to a certain target.

     Local variables can be set on a dependency line, unless
     .MAKE.TARGET_LOCAL_VARIABLES is set to `false'.  The rest of the line
     (which already has had global variables expanded) is the variable value.
     For example:

           COMPILER_WRAPPERS= ccache distcc icecc


     Only the targets `${OBJS}' are impacted by that filter (in "meta" mode)
     and simply enabling/disabling any of the compiler wrappers does not
     render all of those targets out-of-date.

     NOTE: target-local variable assignments behave differently in that;

           +=      Only appends to a previous local assignment for the same
                   target and variable.

           :=      Is redundant with respect to global variables, which have
                   already been expanded.

     The seven built-in local variables are:

           .ALLSRC       The list of all sources for this target; also known
                         as `>'.

           .ARCHIVE      The name of the archive file; also known as `!'.

           .IMPSRC       In suffix-transformation rules, the name/path of the
                         source from which the target is to be transformed
                         (the "implied" source); also known as `<'.  It is not
                         defined in explicit rules.

           .MEMBER       The name of the archive member; also known as `%'.

           .OODATE       The list of sources for this target that were deemed
                         out-of-date; also known as `?'.

           .PREFIX       The file prefix of the target, containing only the
                         file portion, no suffix or preceding directory
                         components; also known as `*'.  The suffix must be
                         one of the known suffixes declared with .SUFFIXES, or
                         it is not recognized.

           .TARGET       The name of the target; also known as `@'.  For
                         compatibility with other makes this is an alias for
                         .ARCHIVE in archive member rules.

     The shorter forms (`>', `!', `<', `%', `?', `*', and `@') are permitted
     for backward compatibility with historical makefiles and legacy POSIX
     make and are not recommended.

     Variants of these variables with the punctuation followed immediately by
     `D' or `F', e.g. `$(@D)', are legacy forms equivalent to using the `:H'
     and `:T' modifiers.  These forms are accepted for compatibility with AT&T
     System V UNIX makefiles and POSIX but are not recommended.

     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 `.TARGET', `.PREFIX', `.ARCHIVE', and `.MEMBER'.

   Additional built-in variables
     In addition, make sets or knows about the following variables:

     .ALLTARGETS     The list of all targets encountered in the makefiles.  If
                     evaluated during makefile parsing, lists only those
                     targets encountered thus far.

     .CURDIR         A path to the directory where make was executed.  Refer
                     to the description of `PWD' for more details.

                     The directory of the file this Makefile was included

                     The filename of the file this Makefile was included from.

     MAKE            The name that make was executed with (argv[0]).  For
                     compatibility, make also sets .MAKE with the same value.
                     The preferred variable to use is the environment variable
                     MAKE because it is more compatible with other make
                     variants and cannot be confused with the special target
                     with the same name.

                     Names the makefile (default `.depend') from which
                     generated dependencies are read.

                     A boolean that controls the default behavior of the -V
                     option.  If true, variable values printed with -V are
                     fully expanded; if false, the raw variable contents
                     (which may include additional unexpanded variable
                     references) are shown.

     .MAKE.EXPORTED  The list of variables exported by make.

     .MAKE.JOBS      The argument to the -j option.

                     If make is run with -j, the output for each target is
                     prefixed with a token
                           --- target ---
                     the first part of which can be controlled via
                     .MAKE.JOB.PREFIX.  If .MAKE.JOB.PREFIX is empty, no token
                     is printed.  For example, setting .MAKE.JOB.PREFIX to
                     `${.newline}---${.MAKE:T}[${.MAKE.PID}]' would produce
                     tokens like
                           ---make[1234] target ---
                     making it easier to track the degree of parallelism being

                     If set to `false', apparent variable assignments in
                     dependency lines are treated as normal sources.

     MAKEFLAGS       The environment variable `MAKEFLAGS' may contain anything
                     that may be specified on make's command line.  Anything
                     specified on make's command line is appended to the
                     MAKEFLAGS variable, which is then added to the
                     environment for all programs that make executes.

     .MAKE.LEVEL     The recursion depth of make.  The top-level instance of
                     make has level 0, and each child make has its parent
                     level plus 1.  This allows tests like: .if ${.MAKE.LEVEL}
                     == 0 to protect things which should only be evaluated in
                     the top-level instance of make.

                     The ordered list of makefile names (default `makefile',
                     `Makefile') that make looks for.

                     The list of makefiles read by make, which is useful for
                     tracking dependencies.  Each makefile is recorded only
                     once, regardless of the number of times read.

     .MAKE.MODE      Processed after reading all makefiles.  Affects the mode
                     that make runs in.  It can contain a number of keywords:

                     compat               Like -B, puts make into "compat"

                     meta                 Puts make into "meta" mode, where
                                          meta files are created for each
                                          target to capture the command run,
                                          the output generated, and if
                                          filemon(4) is available, the system
                                          calls which are of interest to make.
                                          The captured output can be useful
                                          when diagnosing errors.

                     curdirOk=bf          By default, make does not create
                                          .meta files in `.CURDIR'.  This can
                                          be overridden by setting bf to a
                                          value which represents true.

                     missing-meta=bf      If bf is true, a missing .meta file
                                          makes the target out-of-date.

                     missing-filemon=bf   If bf is true, missing filemon data
                                          makes the target out-of-date.

                     nofilemon            Do not use filemon(4).

                     env                  For debugging, it can be useful to
                                          include the environment in the .meta

                     verbose              If in "meta" mode, print a clue
                                          about the target being built.  This
                                          is useful if the build is otherwise
                                          running silently.  The message
                                          printed is the expanded value of

                     ignore-cmd           Some makefiles have commands which
                                          are simply not stable.  This keyword
                                          causes them to be ignored for
                                          determining whether a target is out
                                          of date in "meta" mode.  See also

                     silent=bf            If bf is true, when a .meta file is
                                          created, mark the target .SILENT.

                     randomize-targets    In both compat and parallel mode, do
                                          not make the targets in the usual
                                          order, but instead randomize their
                                          order.  This mode can be used to
                                          detect undeclared dependencies
                                          between files.

                     In "meta" mode, provides a list of prefixes which match
                     the directories controlled by make.  If a file that was
                     generated outside of .OBJDIR but within said bailiwick is
                     missing, the current target is considered out-of-date.

                     In "meta" mode, it can (very rarely!) be useful to filter
                     command lines before comparison.  This variable can be
                     set to a set of modifiers that are applied to each line
                     of the old and new command that differ, if the filtered
                     commands still differ, the target is considered out-of-

                     In "meta" mode, this variable contains a list of all the
                     meta files updated.  If not empty, it can be used to
                     trigger processing of .MAKE.META.FILES.

                     In "meta" mode, this variable contains a list of all the
                     meta files used (updated or not).  This list can be used
                     to process the meta files to extract dependency

                     Provides a list of path prefixes that should be ignored;
                     because the contents are expected to change over time.
                     The default list includes: `/dev /etc /proc /tmp /var/run

                     Provides a list of patterns to match against pathnames.
                     Ignore any that match.

                     Provides a list of variable modifiers to apply to each
                     pathname.  Ignore if the expansion is an empty string.

                     Defines the message printed for each meta file updated in
                     "meta verbose" mode.  The default value is:
                           Building ${.TARGET:H:tA}/${.TARGET:T}

     .MAKEOVERRIDES  This variable is used to record the names of variables
                     assigned to on the command line, so that they may be
                     exported as part of `MAKEFLAGS'.  This behavior can be
                     disabled by assigning an empty value to `.MAKEOVERRIDES'
                     within a makefile.  Extra variables can be exported from
                     a makefile by appending their names to `.MAKEOVERRIDES'.
                     `MAKEFLAGS' is re-exported whenever `.MAKEOVERRIDES' is

                     If make was built with filemon(4) support, this is set to
                     the path of the device node.  This allows makefiles to
                     test for this support.

     .MAKE.PID       The process ID of make.

     .MAKE.PPID      The parent process ID of make.

                     If true, `$$' are preserved when doing `:=' assignments.
                     The default is true, for compatibility with other makes.
                     If set to false, `$$' becomes `$' per normal evaluation

     .MAKE.UID       The numeric ID of the user running make.

     .MAKE.GID       The numeric group ID of the user running make.

                     When make stops due to an error, it sets `.ERROR_TARGET'
                     to the name of the target that failed, `.ERROR_CMD' to
                     the commands of the failed target, and in "meta" mode, it
                     also sets `.ERROR_CWD' to the getcwd(3), and
                     `.ERROR_META_FILE' to the path of the meta file (if any)
                     describing the failed target.  It then prints its name
                     and the value of `.CURDIR' as well as the value of any
                     variables named in `MAKE_PRINT_VAR_ON_ERROR'.

     .newline        This variable is simply assigned a newline character as
                     its value.  This allows expansions using the :@ modifier
                     to put a newline between iterations of the loop rather
                     than a space.  For example, in case of an error, make
                     prints the variable names and their values using:

     .OBJDIR         A path to the directory where the targets are built.  Its
                     value is determined by trying to chdir(2) to the
                     following directories in order and using the first match:

                     1.   ${MAKEOBJDIRPREFIX}${.CURDIR}

                          (Only if `MAKEOBJDIRPREFIX' is set in the
                          environment or on the command line.)

                     2.   ${MAKEOBJDIR}

                          (Only if `MAKEOBJDIR' is set in the environment or
                          on the command line.)

                     3.   ${.CURDIR}/obj.${MACHINE}

                     4.   ${.CURDIR}/obj

                     5.   /usr/obj/${.CURDIR}

                     6.   ${.CURDIR}

                     Variable expansion is performed on the value before it is
                     used, so expressions such as
                     ${.CURDIR:S,^/usr/src,/var/obj,} may be used.  This is
                     especially useful with `MAKEOBJDIR'.

                     `.OBJDIR' may be modified in the makefile via the special
                     target `.OBJDIR'.  In all cases, make changes to the
                     specified directory if it exists, and sets `.OBJDIR' and
                     `PWD' to that directory before executing any targets.

                     Except in the case of an explicit `.OBJDIR' target, make
                     checks that the specified directory is writable and
                     ignores it if not.  This check can be skipped by setting
                     the environment variable `MAKE_OBJDIR_CHECK_WRITABLE' to

     .PARSEDIR       The directory name of the current makefile being parsed.

     .PARSEFILE      The basename of the current makefile being parsed.  This
                     variable and `.PARSEDIR' are both set only while the
                     makefiles are being parsed.  To retain their current
                     values, assign them to a variable using assignment with
                     expansion `:='.

     .PATH           The space-separated list of directories that make
                     searches for files.  To update this search list, use the
                     special target `.PATH' rather than modifying the variable

     PWD             Alternate path to the current directory.  make normally
                     sets `.CURDIR' to the canonical path given by getcwd(3).
                     However, if the environment variable `PWD' is set and
                     gives a path to the current directory, make sets
                     `.CURDIR' to the value of `PWD' instead.  This behavior
                     is disabled if `MAKEOBJDIRPREFIX' is set or `MAKEOBJDIR'
                     contains a variable transform.  `PWD' is set to the value
                     of `.OBJDIR' for all programs which make executes.

     .SHELL          The pathname of the shell used to run target scripts.  It
                     is read-only.

     .SUFFIXES       The list of known suffixes.  It is read-only.

     .TARGETS        The list of targets explicitly specified on the command
                     line, if any.

     VPATH           The colon-separated (":") list of directories that make
                     searches for files.  This variable is supported for
                     compatibility with old make programs only, use `.PATH'

   Variable modifiers
     The general format of a variable expansion is:


     Each modifier begins with a colon.  To escape a colon, precede it with a
     backslash `\'.

     A list of indirect modifiers can be specified via a variable, as follows:

           modifier_variable = modifier[:...]


     In this case, the first modifier in the modifier_variable does not start
     with a colon, since that colon already occurs in the referencing
     variable.  If any of the modifiers in the modifier_variable contains a
     dollar sign (`$'), these must be doubled to avoid early expansion.

     Some modifiers interpret the expression value as a single string, others
     treat the expression value as a whitespace-separated list of words.  When
     splitting a string into words, whitespace can be escaped using double
     quotes, single quotes and backslashes, like in the shell.  The quotes and
     backslashes are retained in the words.

     The supported modifiers are:

     :E   Replaces each word in the variable with its suffix.

     :H   Replaces each word in the variable with its dirname.

          Selects only those words that match pattern.  The standard shell
          wildcard characters (`*', `?', and `[]') may be used.  The wildcard
          characters may be escaped with a backslash (`\').  As a consequence
          of the way values are split into words, matched, and then joined,
          the construct
          removes all leading and trailing whitespace and normalizes the
          inter-word spacing to a single space.

          This is the opposite of `:M', selecting all words which do not match

     :O   Orders the words alphabetically.

     :On  Orders the words numerically.  A number followed by one of `k', `M'
          or `G' is multiplied by the appropriate factor, which is 1024 for
          `k', 1048576 for `M', or 1073741824 for `G'.  Both upper- and lower-
          case letters are accepted.

     :Or  Orders the words in reverse alphabetical order.

          Orders the words in reverse numerical order.

     :Ox  Shuffles the words.  The results are different each time you are
          referring to the modified variable; use the assignment with
          expansion `:=' to prevent such behavior.  For example,

                LIST=                   uno due tre quattro
                RANDOM_LIST=            ${LIST:Ox}
                STATIC_RANDOM_LIST:=    ${LIST:Ox}

                        @echo "${RANDOM_LIST}"
                        @echo "${RANDOM_LIST}"
                        @echo "${STATIC_RANDOM_LIST}"
                        @echo "${STATIC_RANDOM_LIST}"
          may produce output similar to:

                quattro due tre uno
                tre due quattro uno
                due uno quattro tre
                due uno quattro tre

     :Q   Quotes every shell meta-character in the value, so that it can be
          passed safely to the shell.

     :q   Quotes every shell meta-character in the value, and also doubles `$'
          characters so that it can be passed safely through recursive
          invocations of make.  This is equivalent to `:S/\$/&&/g:Q'.

     :R   Replaces each word in the variable with everything but its suffix.

          The value is an integer sequence representing the words of the
          original value, or the supplied count.

          The value is interpreted as a format string for strftime(3), using
          gmtime(3), producing the formatted timestamp.  If a timestamp value
          is not provided or is 0, the current time is used.

          Computes a 32-bit hash of the value and encodes it as 8 hex digits.

          The value is interpreted as a format string for strftime(3), using
          localtime(3), producing the formatted timestamp.  If a timestamp
          value is not provided or is 0, the current time is used.

     :tA  Attempts to convert the value to an absolute path using realpath(3).
          If that fails, the value is unchanged.

     :tl  Converts the value to lower-case letters.

          When joining the words after a modifier that treats the value as
          words, the words are normally separated by a space.  This modifier
          changes the separator to the character c.  If c is omitted, no
          separator is used.  The common escapes (including octal numeric
          codes) work as expected.

     :tu  Converts the value to upper-case letters.

     :tW  Causes subsequent modifiers to treat the value as a single word
          (possibly containing embedded whitespace).  See also `:[*]'.

     :tw  Causes the value to be treated as a list of words.  See also `:[@]'.

          Modifies the first occurrence of old_string in each word of the
          value, replacing it with new_string.  If a `g' is appended to the
          last delimiter of the pattern, all occurrences in each word are
          replaced.  If a `1' is appended to the last delimiter of the
          pattern, only the first occurrence is affected.  If a `W' is
          appended to the last delimiter of the pattern, the value is treated
          as a single word.  If old_string begins with a caret (`^'),
          old_string is anchored at the beginning of each word.  If old_string
          ends with a dollar sign (`$'), it is anchored at the end of each
          word.  Inside new_string, an ampersand (`&') is replaced by
          old_string (without the anchoring `^' or `$').  Any character may be
          used as the delimiter for the parts of the modifier string.  The
          anchoring, ampersand and delimiter characters can be escaped with a
          backslash (`\').

          Variable expansion occurs in the normal fashion inside both
          old_string and new_string with the single exception that a backslash
          is used to prevent the expansion of a dollar sign (`$'), not a
          preceding dollar sign as is usual.

          The :C modifier works like the :S modifier except that the old and
          new strings, instead of being simple strings, are an extended
          regular expression pattern (see regex(3)) and an ed(1)-style
          replacement.  Normally, the first occurrence of the pattern pattern
          in each word of the value is substituted with replacement.  The `1'
          modifier causes the substitution to apply to at most one word; the
          `g' modifier causes the substitution to apply to as many instances
          of the search pattern pattern as occur in the word or words it is
          found in; the `W' modifier causes the value to be treated as a
          single word (possibly containing embedded whitespace).

          As for the :S modifier, the pattern and replacement are subjected to
          variable expansion before being parsed as regular expressions.

     :T   Replaces each word in the variable with its last path component

     :u   Removes adjacent duplicate words (like uniq(1)).

          If the variable name (not its value), when parsed as a .if
          conditional expression, evaluates to true, return as its value the
          true_string, otherwise return the false_string.  Since the variable
          name is used as the expression, :? must be the first modifier after
          the variable name itself--which, of course, usually contains
          variable expansions.  A common error is trying to use expressions
          which actually tests defined(NUMBERS).  To determine if any words
          match "42", you need to use something like:
                ${"${NUMBERS:M42}" != "":?match:no}.

          This is the AT&T System V UNIX style variable substitution.  It must
          be the last modifier specified.  If old_string or new_string do not
          contain the pattern matching character `%', it is assumed that they
          are anchored at the end of each word, so only suffixes or entire
          words may be replaced.  Otherwise `%' is the substring of old_string
          to be replaced in new_string.  If only old_string contains the
          pattern matching character `%', and old_string matches, the result
          is the new_string.  If only the new_string contains the pattern
          matching character `%', it is not treated specially and it is
          printed as a literal `%' on match.  If there is more than one
          pattern matching character `%' in either the new_string or
          old_string, only the first instance is treated specially (as the
          pattern character); all subsequent instances are treated as regular

          Variable expansion occurs in the normal fashion inside both
          old_string and new_string with the single exception that a backslash
          is used to prevent the expansion of a dollar sign (`$'), not a
          preceding dollar sign as is usual.

          This is the loop expansion mechanism from the OSF Development
          Environment (ODE) make.  Unlike .for loops, expansion occurs at the
          time of reference.  For each word in the value, assign the word to
          the variable named varname and evaluate string.  The ODE convention
          is that varname should start and end with a period, for example:
                ${LINKS:@.LINK.@${LN} ${TARGET} ${.LINK.}@}

          However, a single-letter variable is often more readable:

          Saves the current variable value in `$_' or the named var for later
          reference.  Example usage:

                M_cmpv.units = 1 1000 1000000
                M_cmpv = S,., ,g:_:range:@i@+ $${_:[-$$i]} \
                \* $${M_cmpv.units:[$$i]}@:S,^,expr 0 ,1:sh

                .if ${VERSION:${M_cmpv}} < ${3.1.12:L:${M_cmpv}}

          Here `$_' is used to save the result of the `:S' modifier which is
          later referenced using the index values from `:range'.

          If the variable is undefined, newval is the value.  If the variable
          is defined, the existing value is returned.  This is another ODE
          make feature.  It is handy for setting per-target CFLAGS for
          If a value is only required if the variable is undefined, use:

          If the variable is defined, newval is the value.

     :L   The name of the variable is the value.

     :P   The path of the node which has the same name as the variable is the
          value.  If no such node exists or its path is null, the name of the
          variable is used.  In order for this modifier to work, the name
          (node) must at least have appeared on the right-hand side of a

          The output of running cmd is the value.

     :sh  The value is run as a command, and the output becomes the new value.

          The variable is assigned the value str after substitution.  This
          modifier and its variations are useful in obscure situations such as
          wanting to set a variable at a point where a target's shell commands
          are being parsed.  These assignment modifiers always expand to

          The `::' helps avoid false matches with the AT&T System V UNIX style
          := modifier and since substitution always occurs, the ::= form is
          vaguely appropriate.

          As for ::= but only if the variable does not already have a value.

          Append str to the variable.

          Assign the output of cmd to the variable.

          Selects one or more words from the value, or performs other
          operations related to the way in which the value is split into

          An empty value, or a value that consists entirely of white-space, is
          treated as a single word.  For the purposes of the `:[]' modifier,
          the words are indexed both forwards using positive integers (where
          index 1 represents the first word), and backwards using negative
          integers (where index -1 represents the last word).

          The range is subjected to variable expansion, and the expanded
          result is then interpreted as follows:

          index  Selects a single word from the value.

                 Selects all words from start to end, inclusive.  For example,
                 `:[2..-1]' selects all words from the second word to the last
                 word.  If start is greater than end, the words are output in
                 reverse order.  For example, `:[-1..1]' selects all the words
                 from last to first.  If the list is already ordered, this
                 effectively reverses the list, but it is more efficient to
                 use `:Or' instead of `:O:[-1..1]'.

          *      Causes subsequent modifiers to treat the value as a single
                 word (possibly containing embedded whitespace).  Analogous to
                 the effect of $* in Bourne shell.

          0      Means the same as `:[*]'.

          @      Causes subsequent modifiers to treat the value as a sequence
                 of words delimited by whitespace.  Analogous to the effect of
                 $@ in Bourne shell.

          #      Returns the number of words in the value.

     Makefile inclusion, conditional structures and for loops are provided in
     make.  All such structures are identified by a line beginning with a
     single dot (`.') character, followed by the keyword of the directive,
     such as include or if.

   File inclusion
     Files are included with either .include <file> or .include "file".
     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 -I option are searched before the system makefile directory.

     For compatibility with other make variants, `include file ...' (without
     leading dot) is also accepted.

     If the include statement is written as .-include or as .sinclude, errors
     locating and/or opening include files are ignored.

     If the include statement is written as .dinclude, not only are errors
     locating and/or opening include files ignored, but stale dependencies
     within the included file are ignored just like in .MAKE.DEPENDFILE.

   Exporting variables
     The directives for exporting and unexporting variables are:

     .export variable ...
             Export the specified global variable.  If no variable list is
             provided, all globals are exported except for internal variables
             (those that start with `.').  This is not affected by the -X
             flag, so should be used with caution.  For compatibility with
             other make programs, export variable=value (without leading dot)
             is also accepted.

             Appending a variable name to .MAKE.EXPORTED is equivalent to
             exporting a variable.

     .export-env variable ...
             The same as `.export', except that the variable is not appended
             to .MAKE.EXPORTED.  This allows exporting a value to the
             environment which is different from that used by make internally.

     .export-literal variable ...
             The same as `.export-env', except that variables in the value are
             not expanded.

     .unexport variable ...
             The opposite of `.export'.  The specified global variable is
             removed from .MAKE.EXPORTED.  If no variable list is provided,
             all globals are unexported, and .MAKE.EXPORTED deleted.

             Unexport all globals previously exported and clear the
             environment inherited from the parent.  This operation causes a
             memory leak of the original environment, so should be used
             sparingly.  Testing for .MAKE.LEVEL being 0 would make sense.
             Also note that any variables which originated in the parent
             environment should be explicitly preserved if desired.  For

                   .if ${.MAKE.LEVEL} == 0
                   PATH := ${PATH}
                   .export PATH

             Would result in an environment containing only `PATH', which is
             the minimal useful environment.  Actually `.MAKE.LEVEL' is also
             pushed into the new environment.

     The directives for printing messages to the output are:

     .info message
             The message is printed along with the name of the makefile and
             line number.

     .warning message
             The message prefixed by `warning:' is printed along with the name
             of the makefile and line number.

     .error message
             The message is printed along with the name of the makefile and
             line number, make exits immediately.

     The directives for conditionals are:

     .if [!]expression [operator expression ...]
             Test the value of an expression.

     .ifdef [!]variable [operator variable ...]
             Test the value of a variable.

     .ifndef [!]variable [operator variable ...]
             Test the value of a variable.

     .ifmake [!]target [operator target ...]
             Test the target being requested.

     .ifnmake [!]target [operator target ...]
             Test the target being requested.

     .else   Reverse the sense of the last conditional.

     .elif [!]expression [operator expression ...]
             A combination of `.else' followed by `.if'.

     .elifdef [!]variable [operator variable ...]
             A combination of `.else' followed by `.ifdef'.

     .elifndef [!]variable [operator variable ...]
             A combination of `.else' followed by `.ifndef'.

     .elifmake [!]target [operator target ...]
             A combination of `.else' followed by `.ifmake'.

     .elifnmake [!]target [operator target ...]
             A combination of `.else' followed by `.ifnmake'.

     .endif  End the body of the conditional.

     The operator may be any one of the following:

     ||     Logical OR.

     &&     Logical AND; of higher precedence than `||'.

     make only evaluates a conditional as far as is necessary to determine its
     value.  Parentheses can be used to override the operator precedence.  The
     boolean operator `!' may be used to logically negate an entire
     conditional.  It is of higher precedence than `&&'.

     The value of expression may be any of the following:

     defined  Takes a variable name as an argument and evaluates to true if
              the variable has been defined.

     make     Takes a target name as an argument and evaluates to true if the
              target was specified as part of make's command line or was
              declared the default target (either implicitly or explicitly,
              see .MAIN) before the line containing the conditional.

     empty    Takes a variable name, with possible modifiers, and evaluates to
              true if the expansion of the variable results in an empty

     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 .PATH).

     target   Takes a target name as an argument and evaluates to true if the
              target has been defined.

              Takes a target name as an argument and evaluates to true if the
              target has been defined and has commands associated with it.

     Expression may also be an arithmetic or string comparison.  Variable
     expansion is performed on both sides of the comparison.  If both sides
     are numeric and neither is enclosed in quotes, the comparison is done
     numerically, otherwise lexicographically.  A string is interpreted as
     hexadecimal integer if it is preceded by 0x, otherwise it is a decimal
     floating-point number; octal numbers are not supported.

     All comparisons may use the operators `==' and `!='.  Numeric comparisons
     may also use the operators `<', `<=', `>' and `>='.

     If the comparison has neither a comparison operator nor a right side, the
     expression evaluates to true if it is nonempty and its numeric value (if
     any) is not zero.

     When make is evaluating one of these conditional expressions, and it
     encounters a (whitespace separated) word it doesn't recognize, either the
     "make" or "defined" function is applied to it, depending on the form of
     the conditional.  If the form is `.ifdef', `.ifndef' or `.if', the
     "defined" function is applied.  Similarly, if the form is `.ifmake' or
     `.ifnmake', the "make" function is applied.

     If the conditional evaluates to true, parsing of the makefile continues
     as before.  If it evaluates to false, the following lines are skipped.
     In both cases, this continues until the corresponding `.else' or `.endif'
     is found.

   For loops
     For loops are typically used to apply a set of rules to a list of files.
     The syntax of a for loop is:

     .for variable [variable ...] in expression

     The expression is expanded and then split into words.  On each iteration
     of the loop, one word is taken and assigned to each variable, in order,
     and these variables are substituted into the make-lines inside the body
     of the for loop.  The number of words must come out even; that is, if
     there are three iteration variables, the number of words provided must be
     a multiple of three.

     If `.break' is encountered within a .for loop, it causes early
     termination of the loop, otherwise a parse error.

   Other directives
     .undef variable ...
             Un-define the specified global variables.  Only global variables
             can be un-defined.

     Comments begin with a hash (`#') character, anywhere but in a shell
     command line, and continue to the end of an unescaped new line.

     .EXEC     Target is never out of date, but always execute commands

     .IGNORE   Ignore any errors from the commands associated with this
               target, exactly as if they all were preceded by a dash (`-').

     .MADE     Mark all sources of this target as being up to date.

     .MAKE     Execute the commands associated with this target even if the -n
               or -t options were specified.  Normally used to mark recursive

     .META     Create a meta file for the target, even if it is flagged as
               .PHONY, .MAKE, or .SPECIAL.  Usage in conjunction with .MAKE is
               the most likely case.  In "meta" mode, the target is out-of-
               date if the meta file is missing.

     .NOMETA   Do not create a meta file for the target.  Meta files are also
               not created for .PHONY, .MAKE, or .SPECIAL targets.

               Ignore differences in commands when deciding if target is out
               of date.  This is useful if the command contains a value which
               always changes.  If the number of commands change, though, the
               target is still considered out of date.  The same effect
               applies to any command line that uses the variable .OODATE,
               which can be used for that purpose even when not otherwise
               needed or desired:

                             @echo this is compared
                             @echo this is not ${.OODATE:M.NOMETA_CMP}
                             @echo this is also compared

               The :M pattern suppresses any expansion of the unwanted

     .NOPATH   Do not search for the target in the directories specified by

     .NOTMAIN  Normally make 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.

               If a target is marked with this attribute and make can't figure
               out how to create it, it ignores this fact and assumes the file
               isn't needed or already exists.

     .PHONY    The target does not correspond to an actual file; it is always
               considered to be out of date, and is not created with the -t
               option.  Suffix-transformation rules are not applied to .PHONY

               When make is interrupted, it normally removes any partially
               made targets.  This source prevents the target from being

               Synonym for .MAKE.

     .SILENT   Do not echo any of the commands associated with this target,
               exactly as if they all were preceded by an at sign (`@').

     .USE      Turn the target into make'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
               .USE) of the source.  If the target already has commands, the
               .USE target's commands are appended to them.

               Like .USE, but instead of appending, prepend the .USEBEFORE
               target commands to the target.

     .WAIT     If .WAIT appears in a dependency line, the sources that precede
               it are made before the sources that succeed it in the line.
               Since the dependents of files are not made until the file
               itself could be made, this also stops the dependents being
               built unless they are needed for another branch of the
               dependency tree.  So given:

               x: a .WAIT b
                       echo x
                       echo a
               b: b1
                       echo b
                       echo b1

               the output is always `a', `b1', `b', `x'.

               The ordering imposed by .WAIT is only relevant for parallel

     Special targets may not be included with other targets, i.e. they must be
     the only target specified.

     .BEGIN   Any command lines attached to this target are executed before
              anything else is done.

              This is sort of a .USE rule for any target (that was used only
              as a source) that make can't figure out any other way to create.
              Only the shell script is used.  The .IMPSRC variable of a target
              that inherits .DEFAULT's commands is set to the target's own

              If this target is present in the makefile, it globally causes
              make to delete targets whose commands fail.  (By default, only
              targets whose commands are interrupted during execution are
              deleted.  This is the historical behavior.)  This setting can be
              used to help prevent half-finished or malformed targets from
              being left around and corrupting future rebuilds.

     .END     Any command lines attached to this target are executed after
              everything else is done successfully.

     .ERROR   Any command lines attached to this target are executed when
              another target fails.  The .ERROR_TARGET variable is set to the
              target that failed.  See also MAKE_PRINT_VAR_ON_ERROR.

     .IGNORE  Mark each of the sources with the .IGNORE attribute.  If no
              sources are specified, this is the equivalent of specifying the
              -i option.

              If make is interrupted, the commands for this target are

     .MAIN    If no target is specified when make is invoked, this target is

              This target provides a way to specify flags for make at the time
              when the makefiles are read.  The flags are as if typed to the
              shell, though the -f option has no effect.

     .NOPATH  Apply the .NOPATH attribute to any specified sources.

              Disable parallel mode.

              Synonym for .NOTPARALLEL, for compatibility with other pmake

     .OBJDIR  The source is a new value for `.OBJDIR'.  If it exists, make
              changes the current working directory to it and updates the
              value of `.OBJDIR'.

     .ORDER   In parallel mode, the named targets are made in sequence.  This
              ordering does not add targets to the list of targets to be made.

              Since the dependents of a target do not get built until the
              target itself could be built, unless `a' is built by another
              part of the dependency graph, the following is a dependency

              .ORDER: b a
              b: a

     .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 removed from
              the search path.  If the source is the special .DOTLAST target,
              the current working directory is searched last.

              Like .PATH but applies only to files with a particular suffix.
              The suffix must have been previously declared with .SUFFIXES.

     .PHONY   Apply the .PHONY attribute to any specified sources.

     .POSIX   If this is the first non-comment line in the main makefile, the
              variable %POSIX is set to the value `1003.2' and the makefile
              `<posix.mk>' is included if it exists, to provide POSIX-
              compatible default rules.  If make is run with the -r flag, only
              `posix.mk' contributes to the default rules.

              Apply the .PRECIOUS attribute to any specified sources.  If no
              sources are specified, the .PRECIOUS attribute is applied to
              every target in the file.

     .SHELL   Sets the shell that make uses to execute commands.  The sources
              are a set of field=value pairs.

              name            This is the minimal specification, used to
                              select one of the built-in shell specs; sh, ksh,
                              and csh.

              path            Specifies the absolute path to the shell.

              hasErrCtl       Indicates whether the shell supports exit on

              check           The command to turn on error checking.

              ignore          The command to disable error checking.

              echo            The command to turn on echoing of commands

              quiet           The command to turn off echoing of commands

              filter          The output to filter after issuing the quiet
                              command.  It is typically identical to quiet.

              errFlag         The flag to pass the shell to enable error

              echoFlag        The flag to pass the shell to enable command

              newline         The string literal to pass the shell that
                              results in a single newline character when used
                              outside of any quoting characters.

              .SHELL: name=ksh path=/bin/ksh hasErrCtl=true \
                      check="set -e" ignore="set +e" \
                      echo="set -v" quiet="set +v" filter="set +v" \
                      echoFlag=v errFlag=e newline="'\n'"

     .SILENT  Apply the .SILENT attribute to any specified sources.  If no
              sources are specified, the .SILENT attribute is applied to every
              command in the file.

     .STALE   This target gets run when a dependency file contains stale
              entries, having .ALLSRC set to the name of that dependency file.

              Each source specifies a suffix to make.  If no sources are
              specified, any previously specified suffixes are deleted.  It
              allows the creation of suffix-transformation rules.


              .SUFFIXES: .o
                      cc -o ${.TARGET} -c ${.IMPSRC}

     make uses the following environment variables, if they exist: MACHINE,
     PWD, and TMPDIR.

     MAKEOBJDIRPREFIX and MAKEOBJDIR may only be set in the environment or on
     the command line to make and not as makefile variables; see the
     description of `.OBJDIR' for more details.

     .depend        list of dependencies
     Makefile       list of dependencies
     makefile       list of dependencies
     sys.mk         system makefile
     /usr/share/mk  system makefile directory

     The basic make syntax is compatible between different make variants;
     however the special variables, variable modifiers and conditionals are

   Older versions
     An incomplete list of changes in older versions of make:

     The way that .for loop variables are substituted changed after NetBSD 5.0
     so that they still appear to be variable expansions.  In particular this
     stops them being treated as syntax, and removes some obscure problems
     using them in .if statements.

     The way that parallel makes are scheduled changed in NetBSD 4.0 so that
     .ORDER and .WAIT apply recursively to the dependent nodes.  The
     algorithms used may change again in the future.

   Other make dialects
     Other make dialects (GNU make, SVR4 make, POSIX make, etc.) do not
     support most of the features of make as described in this manual.  Most

              The .WAIT and .ORDER declarations and most functionality
               pertaining to parallelization.  (GNU make supports
               parallelization but lacks these features needed to control it

              Directives, including for loops and conditionals and most of
               the forms of include files.  (GNU make has its own incompatible
               and less powerful syntax for conditionals.)

              All built-in variables that begin with a dot.

              Most of the special sources and targets that begin with a dot,
               with the notable exception of .PHONY, .PRECIOUS, and .SUFFIXES.

              Variable modifiers, except for the
               string substitution, which does not portably support globbing
               with `%' and historically only works on declared suffixes.

              The $> variable even in its short form; most makes support this
               functionality but its name varies.

     Some features are somewhat more portable, such as assignment with +=, ?=,
     and !=.  The .PATH functionality is based on an older feature VPATH found
     in GNU make and many versions of SVR4 make; however, historically its
     behavior is too ill-defined (and too buggy) to rely upon.

     The $@ and $< variables are more or less universally portable, as is the
     $(MAKE) variable.  Basic use of suffix rules (for files only in the
     current directory, not trying to chain transformations together, etc.) is
     also reasonably portable.


     A make command appeared in Version 7 AT&T UNIX.  This make implementation
     is based on Adam de Boor's pmake program, which was written for Sprite at
     Berkeley.  It was designed to be a parallel distributed make running jobs
     on different machines using a daemon called "customs".

     Historically the target/dependency FRC has been used to FoRCe rebuilding
     (since the target/dependency does not exist... unless someone creates an
     FRC file).

     The make syntax is difficult to parse without actually acting on the
     data.  For instance, finding the end of a variable's use should involve
     scanning each of the modifiers, using the correct terminator for each
     field.  In many places make just counts {} and () in order to find the
     end of a variable expansion.

     There is no way of escaping a space character in a filename.

NetBSD 9.99                   September 12, 2022                   NetBSD 9.99