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execute_process

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execute_process

Execute one or more child processes.

.. code-block:: cmake

execute_process(COMMAND <cmd1> [<arguments>] [COMMAND <cmd2> [<arguments>]]... [WORKING_DIRECTORY <directory>] [TIMEOUT <seconds>] [RESULT_VARIABLE <variable>] [RESULTS_VARIABLE <variable>] [OUTPUT_VARIABLE <variable>] [ERROR_VARIABLE <variable>] [INPUT_FILE <file>] [OUTPUT_FILE <file>] [ERROR_FILE <file>] [OUTPUT_QUIET] [ERROR_QUIET] [COMMAND_ECHO <where>] [OUTPUT_STRIP_TRAILING_WHITESPACE] [ERROR_STRIP_TRAILING_WHITESPACE] [ENCODING <name>] [ECHO_OUTPUT_VARIABLE] [ECHO_ERROR_VARIABLE] [COMMAND_ERROR_IS_FATAL <ANY|LAST|NONE>])

Runs the given sequence of one or more commands.

Commands are executed concurrently as a pipeline, with the standard output of each process piped to the standard input of the next. A single standard error pipe is used for all processes.

execute_process runs commands while CMake is configuring the project, prior to build system generation. Use the :command:add_custom_target and :command:add_custom_command commands to create custom commands that run at build time.

Options:

COMMAND A child process command line.

CMake executes the child process using operating system APIs directly:

  • On POSIX platforms, the command line is passed to the child process in an argv[] style array. No intermediate shell is executed, so shell operators such as > are treated as normal arguments.

  • On Windows platforms, the command line is encoded as a string such that child processes using CommandLineToArgvW_ will decode the original arguments.

    If the command runs a .exe, .com, or other executable, no intermediate command interpreter is executed, so shell operators such as > are treated as normal arguments.

    If the command runs a .bat or .cmd script, it is executed through the cmd command interpreter. The command interpreter does not use CommandLineToArgvW_, so some arguments may be received by the script with extra quoting.

    .. versionchanged:: 4.0 .bat and .cmd scripts are now explicitly executed through the command interpreter by prepending cmd /c call to the command line. Previously, they were implicitly executed through cmd /c, without call, by undocumented behavior of CreateProcessW_.

Use the INPUT_*, OUTPUT_*, and ERROR_* options to redirect stdin, stdout, and stderr.

For sequential execution of multiple commands use multiple execute_process calls each with a single COMMAND argument.

WORKING_DIRECTORY The named directory will be set as the current working directory of the child processes. If not given, the child processes' working directory is unspecified.

TIMEOUT After the specified number of seconds (fractions allowed), all unfinished child processes will be terminated, and the RESULT_VARIABLE will be set to a string mentioning the "timeout".

RESULT_VARIABLE The variable will be set to contain the result of last child process. This will be an integer return code from the last child or a string describing an error condition.

RESULTS_VARIABLE <variable> .. versionadded:: 3.10

The variable will be set to contain the result of all processes as a :ref:semicolon-separated list <CMake Language Lists>, in order of the given COMMAND arguments. Each entry will be an integer return code from the corresponding child or a string describing an error condition.

INPUT_FILE <file> <file> is attached to the standard input pipe of the first COMMAND process.

OUTPUT_FILE <file> <file> is attached to the standard output pipe of the last COMMAND process.

ERROR_FILE <file> <file> is attached to the standard error pipe of all COMMAND processes.

.. versionadded:: 3.3 If the same <file> is named for both OUTPUT_FILE and ERROR_FILE then it will be used for both standard output and standard error pipes.

OUTPUT_QUIET, ERROR_QUIET The standard output on OUTPUT_VARIABLE or standard error on ERROR_VARIABLE are not connected (no variable content). The *_FILE and ECHO_*_VARIABLE options are not affected.

OUTPUT_VARIABLE, ERROR_VARIABLE The variable named will be set with the contents of the standard output and standard error pipes, respectively. If the same variable is named for both pipes their output will be merged in the order produced.

OUTPUT_STRIP_TRAILING_WHITESPACE, ERROR_STRIP_TRAILING_WHITESPACE Removes whitespace characters from the end of the values stored in the corresponding OUTPUT_VARIABLE and ERROR_VARIABLE variables.

ECHO_OUTPUT_VARIABLE, ECHO_ERROR_VARIABLE .. versionadded:: 3.18

The standard output or standard error will not be exclusively redirected to the specified variables.

The output will be duplicated into the specified variables and also onto standard output or standard error analogous to the tee Unix command.

.. note:: If more than one OUTPUT_* or ERROR_* option is given for the same pipe the precedence is not specified. If no OUTPUT_* or ERROR_* options are given the output will be shared with the corresponding pipes of the CMake process itself.

COMMAND_ECHO <where> .. versionadded:: 3.15

The command being run will be echo'ed to <where> with <where> being set to one of STDERR, STDOUT or NONE. See the :variable:CMAKE_EXECUTE_PROCESS_COMMAND_ECHO variable for a way to control the default behavior when this option is not present.

ENCODING <name> .. versionadded:: 3.8

On Windows, the encoding that is used to decode output from the process. Ignored on other platforms. Valid encoding names are:

NONE Perform no decoding. This assumes that the process output is encoded in the same way as CMake's internal encoding (UTF-8).

This was the default in CMake 3.14 and older.

AUTO Use the current active console's codepage or if that isn't available then use ANSI.

This was the default in CMake 3.15 through 3.30.

ANSI Use the ANSI codepage.

OEM Use the original equipment manufacturer (OEM) code page.

UTF-8 .. versionadded:: 3.11

Use the UTF-8 codepage.

This is the default since CMake 3.31. See policy :policy:CMP0176.

UTF8 Use the UTF-8 codepage. Use of this name is discouraged in favor of UTF-8 to match the UTF-8 RFC <https://datatracker.ietf.org/doc/html/rfc3629>_ naming convention.

COMMAND_ERROR_IS_FATAL <ANY|LAST|NONE> .. versionadded:: 3.19

The option following COMMAND_ERROR_IS_FATAL determines the behavior when an error is encountered:

ANY If any of the commands in the list of commands fail, the execute_process() command halts with an error.

LAST If the last command in the list of commands fails, the execute_process() command halts with an error. Commands earlier in the list will not cause a fatal error.

NONE .. versionadded:: 4.0

Regardless of any of the commands failing, the ``execute_process()``
command will not halt with an error.

.. versionadded:: 4.0

If not provided, the
:variable:`CMAKE_EXECUTE_PROCESS_COMMAND_ERROR_IS_FATAL` variable
is checked.  If the variable is not set, the default is ``NONE``.
If ``RESULT_VARIABLE`` or ``RESULTS_VARIABLE`` is supplied,
:variable:`CMAKE_EXECUTE_PROCESS_COMMAND_ERROR_IS_FATAL` is ignored.

.. _CommandLineToArgvW: https://learn.microsoft.com/en-us/windows/win32/api/shellapi/nf-shellapi-commandlinetoargvw .. _CreateProcessW: https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-createprocessw