add_custom_target

Add a target with no output so it will always be built.

add_custom_target(Name [ALL] [command1 [args1...]]
                  [COMMAND command2 [args2...] ...]
                  [DEPENDS depend depend depend ... ]
                  [BYPRODUCTS [files...]]
                  [WORKING_DIRECTORY dir]
                  [COMMENT comment]
                  [JOB_POOL job_pool]
                  [JOB_SERVER_AWARE <bool>]
                  [VERBATIM] [USES_TERMINAL]
                  [COMMAND_EXPAND_LISTS]
                  [SOURCES src1 [src2...]])

Adds a target with the given name that executes the given commands. The target has no output file and is always considered out of date even if the commands try to create a file with the name of the target. Use the add_custom_command() command to generate a file with dependencies. By default nothing depends on the custom target. Use the add_dependencies() command to add dependencies to or from other targets.

The options are:

ALL

Indicate that this target should be added to the default build target so that it will be run every time (the command cannot be called ALL).

BYPRODUCTS

Added in version 3.2.

Specify the files the command is expected to produce but whose modification time may or may not be updated on subsequent builds. If a byproduct name is a relative path it will be interpreted relative to the build tree directory corresponding to the current source directory. Each byproduct file will be marked with the GENERATED source file property automatically.

See policy CMP0058 for the motivation behind this feature.

Explicit specification of byproducts is supported by the Ninja generator to tell the ninja build tool how to regenerate byproducts when they are missing. It is also useful when other build rules (e.g. custom commands) depend on the byproducts. Ninja requires a build rule for any generated file on which another rule depends even if there are order-only dependencies to ensure the byproducts will be available before their dependents build.

The Makefile Generators will remove BYPRODUCTS and other GENERATED files during make clean.

Added in version 3.20: Arguments to BYPRODUCTS may use a restricted set of generator expressions. Target-dependent expressions are not permitted.

Changed in version 3.28: In custom targets using File Sets, byproducts are now considered private unless they are listed in a non-private file set. See policy CMP0154.

COMMAND

Specify the command-line(s) to execute at build time. If more than one COMMAND is specified they will be executed in order, but not necessarily composed into a stateful shell or batch script. (To run a full script, use the configure_file() command or the file(GENERATE) command to create it, and then specify a COMMAND to launch it.)

If COMMAND specifies an executable target name (created by the add_executable() command), it will automatically be replaced by the location of the executable created at build time if either of the following is true:

  • The target is not being cross-compiled (i.e. the CMAKE_CROSSCOMPILING variable is not set to true).

  • Added in version 3.6: The target is being cross-compiled and an emulator is provided (i.e. its CROSSCOMPILING_EMULATOR target property is set). In this case, the contents of CROSSCOMPILING_EMULATOR will be prepended to the command before the location of the target executable.

If neither of the above conditions are met, it is assumed that the command name is a program to be found on the PATH at build time.

Arguments to COMMAND may use generator expressions. Use the TARGET_FILE generator expression to refer to the location of a target later in the command line (i.e. as a command argument rather than as the command to execute).

Whenever one of the following target based generator expressions are used as a command to execute or is mentioned in a command argument, a target-level dependency will be added automatically so that the mentioned target will be built before this custom target (see policy CMP0112).

  • TARGET_FILE

  • TARGET_LINKER_FILE

  • TARGET_SONAME_FILE

  • TARGET_PDB_FILE

The command and arguments are optional and if not specified an empty target will be created.

COMMENT

Display the given message before the commands are executed at build time.

Added in version 3.26: Arguments to COMMENT may use generator expressions.

DEPENDS

Reference files and outputs of custom commands created with add_custom_command() command calls in the same directory (CMakeLists.txt file). They will be brought up to date when the target is built.

Changed in version 3.16: A target-level dependency is added if any dependency is a byproduct of a target or any of its build events in the same directory to ensure the byproducts will be available before this target is built.

Use the add_dependencies() command to add dependencies on other targets.

COMMAND_EXPAND_LISTS

Added in version 3.8.

Lists in COMMAND arguments will be expanded, including those created with generator expressions, allowing COMMAND arguments such as ${CC} "-I$<JOIN:$<TARGET_PROPERTY:foo,INCLUDE_DIRECTORIES>,;-I>" foo.cc to be properly expanded.

JOB_POOL

Added in version 3.15.

Specify a pool for the Ninja generator. Incompatible with USES_TERMINAL, which implies the console pool. Using a pool that is not defined by JOB_POOLS causes an error by ninja at build time.

JOB_SERVER_AWARE

Added in version 3.28.

Specify that the command is GNU Make job server aware.

For the Unix Makefiles, MSYS Makefiles, and MinGW Makefiles generators this will add the + prefix to the recipe line. See the GNU Make Documentation for more information.

This option is silently ignored by other generators.

SOURCES

Specify additional source files to be included in the custom target. Specified source files will be added to IDE project files for convenience in editing even if they have no build rules.

VERBATIM

All arguments to the commands will be escaped properly for the build tool so that the invoked command receives each argument unchanged. Note that one level of escapes is still used by the CMake language processor before add_custom_target even sees the arguments. Use of VERBATIM is recommended as it enables correct behavior. When VERBATIM is not given the behavior is platform specific because there is no protection of tool-specific special characters.

USES_TERMINAL

Added in version 3.2.

The command will be given direct access to the terminal if possible. With the Ninja generator, this places the command in the console pool.

WORKING_DIRECTORY

Execute the command with the given current working directory. If it is a relative path it will be interpreted relative to the build tree directory corresponding to the current source directory.

Added in version 3.13: Arguments to WORKING_DIRECTORY may use generator expressions.

Ninja Multi-Config

Added in version 3.20: add_custom_target supports the Ninja Multi-Config generator's cross-config capabilities. See the generator documentation for more information.

See Also