File: make.info,  Node: Special Targets,  Next: Multiple Targets,  Prev: Empty Targets,  Up: Rules

4.9 Special Built-in Target Names
=================================

Certain names have special meanings if they appear as targets.

'.PHONY'

     The prerequisites of the special target '.PHONY' are considered to
     be phony targets.  When it is time to consider such a target,
     'make' will run its recipe unconditionally, regardless of whether a
     file with that name exists or what its last-modification time is.
     *Note Phony Targets: Phony Targets.

'.SUFFIXES'

     The prerequisites of the special target '.SUFFIXES' are the list of
     suffixes to be used in checking for suffix rules.  *Note
     Old-Fashioned Suffix Rules: Suffix Rules.

'.DEFAULT'

     The recipe specified for '.DEFAULT' is used for any target for
     which no rules are found (either explicit rules or implicit rules).
     *Note Last Resort::.  If a '.DEFAULT' recipe is specified, every
     file mentioned as a prerequisite, but not as a target in a rule,
     will have that recipe executed on its behalf.  *Note Implicit Rule
     Search Algorithm: Implicit Rule Search.

'.PRECIOUS'

     The targets which '.PRECIOUS' depends on are given the following
     special treatment: if 'make' is killed or interrupted during the
     execution of their recipes, the target is not deleted.  *Note
     Interrupting or Killing 'make': Interrupts.  Also, if the target is
     an intermediate file, it will not be deleted after it is no longer
     needed, as is normally done.  *Note Chains of Implicit Rules:
     Chained Rules.  In this latter respect it overlaps with the
     '.SECONDARY' special target.

     You can also list the target pattern of an implicit rule (such as
     '%.o') as a prerequisite file of the special target '.PRECIOUS' to
     preserve intermediate files created by rules whose target patterns
     match that file's name.

'.INTERMEDIATE'

     The targets which '.INTERMEDIATE' depends on are treated as
     intermediate files.  *Note Chains of Implicit Rules: Chained Rules.
     '.INTERMEDIATE' with no prerequisites has no effect.

'.NOTINTERMEDIATE'

     Prerequisites of the special target '.NOTINTERMEDIATE' are never
     considered intermediate files.  *Note Chains of Implicit Rules:
     Chained Rules.  '.NOTINTERMEDIATE' with no prerequisites causes all
     targets to be treated as not intermediate.

     If the prerequisite is a target pattern then targets that are built
     using that pattern rule are not considered intermediate.

'.SECONDARY'

     The targets which '.SECONDARY' depends on are treated as
     intermediate files, except that they are never automatically
     deleted.  *Note Chains of Implicit Rules: Chained Rules.

     '.SECONDARY' can be used to avoid redundant rebuilds in some
     unusual situations.  For example:

          hello.bin: hello.o bye.o
                  $(CC) -o $@ $^

          %.o: %.c
                  $(CC) -c -o $@ $<

          .SECONDARY: hello.o bye.o

     Suppose 'hello.bin' is up to date in regards to the source files,
     _but_ the object file 'hello.o' is missing.  Without '.SECONDARY'
     make would rebuild 'hello.o' then rebuild 'hello.bin' even though
     the source files had not changed.  By declaring 'hello.o' as
     '.SECONDARY' 'make' will not need to rebuild it and won't need to
     rebuild 'hello.bin' either.  Of course, if one of the source files
     _were_ updated then all object files would be rebuilt so that the
     creation of 'hello.bin' could succeed.

     '.SECONDARY' with no prerequisites causes all targets to be treated
     as secondary (i.e., no target is removed because it is considered
     intermediate).

'.SECONDEXPANSION'

     If '.SECONDEXPANSION' is mentioned as a target anywhere in the
     makefile, then all prerequisite lists defined _after_ it appears
     will be expanded a second time after all makefiles have been read
     in.  *Note Secondary Expansion: Secondary Expansion.

'.DELETE_ON_ERROR'

     If '.DELETE_ON_ERROR' is mentioned as a target anywhere in the
     makefile, then 'make' will delete the target of a rule if it has
     changed and its recipe exits with a nonzero exit status, just as it
     does when it receives a signal.  *Note Errors in Recipes: Errors.

'.IGNORE'

     If you specify prerequisites for '.IGNORE', then 'make' will ignore
     errors in execution of the recipe for those particular files.  The
     recipe for '.IGNORE' (if any) is ignored.

     If mentioned as a target with no prerequisites, '.IGNORE' says to
     ignore errors in execution of recipes for all files.  This usage of
     '.IGNORE' is supported only for historical compatibility.  Since
     this affects every recipe in the makefile, it is not very useful;
     we recommend you use the more selective ways to ignore errors in
     specific recipes.  *Note Errors in Recipes: Errors.

'.LOW_RESOLUTION_TIME'

     If you specify prerequisites for '.LOW_RESOLUTION_TIME', 'make'
     assumes that these files are created by commands that generate low
     resolution time stamps.  The recipe for the '.LOW_RESOLUTION_TIME'
     target are ignored.

     The high resolution file time stamps of many modern file systems
     lessen the chance of 'make' incorrectly concluding that a file is
     up to date.  Unfortunately, some hosts do not provide a way to set
     a high resolution file time stamp, so commands like 'cp -p' that
     explicitly set a file's time stamp must discard its sub-second
     part.  If a file is created by such a command, you should list it
     as a prerequisite of '.LOW_RESOLUTION_TIME' so that 'make' does not
     mistakenly conclude that the file is out of date.  For example:

          .LOW_RESOLUTION_TIME: dst
          dst: src
                  cp -p src dst

     Since 'cp -p' discards the sub-second part of 'src''s time stamp,
     'dst' is typically slightly older than 'src' even when it is up to
     date.  The '.LOW_RESOLUTION_TIME' line causes 'make' to consider
     'dst' to be up to date if its time stamp is at the start of the
     same second that 'src''s time stamp is in.

     Due to a limitation of the archive format, archive member time
     stamps are always low resolution.  You need not list archive
     members as prerequisites of '.LOW_RESOLUTION_TIME', as 'make' does
     this automatically.

'.SILENT'

     If you specify prerequisites for '.SILENT', then 'make' will not
     print the recipe used to remake those particular files before
     executing them.  The recipe for '.SILENT' is ignored.

     If mentioned as a target with no prerequisites, '.SILENT' says not
     to print any recipes before executing them.  You may also use more
     selective ways to silence specific recipe command lines.  *Note
     Recipe Echoing: Echoing.  If you want to silence all recipes for a
     particular run of 'make', use the '-s' or '--silent' option (*note
     Options Summary::).

'.EXPORT_ALL_VARIABLES'

     Simply by being mentioned as a target, this tells 'make' to export
     all variables to child processes by default.  This is an
     alternative to using 'export' with no arguments.  *Note
     Communicating Variables to a Sub-'make': Variables/Recursion.

'.NOTPARALLEL'

     If '.NOTPARALLEL' is mentioned as a target with no prerequisites,
     all targets in this invocation of 'make' will be run serially, even
     if the '-j' option is given.  Any recursively invoked 'make'
     command will still run recipes in parallel (unless its makefile
     also contains this target).

     If '.NOTPARALLEL' has targets as prerequisites, then all the
     prerequisites of those targets will be run serially.  This
     implicitly adds a '.WAIT' between each prerequisite of the listed
     targets.  *Note Disabling Parallel Execution: Parallel Disable.

'.ONESHELL'

     If '.ONESHELL' is mentioned as a target, then when a target is
     built all lines of the recipe will be given to a single invocation
     of the shell rather than each line being invoked separately.  *Note
     Recipe Execution: Execution.

'.POSIX'

     If '.POSIX' is mentioned as a target, then the makefile will be
     parsed and run in POSIX-conforming mode.  This does _not_ mean that
     only POSIX-conforming makefiles will be accepted: all advanced GNU
     'make' features are still available.  Rather, this target causes
     'make' to behave as required by POSIX in those areas where 'make''s
     default behavior differs.

     In particular, if this target is mentioned then recipes will be
     invoked as if the shell had been passed the '-e' flag: the first
     failing command in a recipe will cause the recipe to fail
     immediately.

   Any defined implicit rule suffix also counts as a special target if
it appears as a target, and so does the concatenation of two suffixes,
such as '.c.o'.  These targets are suffix rules, an obsolete way of
defining implicit rules (but a way still widely used).  In principle,
any target name could be special in this way if you break it in two and
add both pieces to the suffix list.  In practice, suffixes normally
begin with '.', so these special target names also begin with '.'.
*Note Old-Fashioned Suffix Rules: Suffix Rules.