execute_process

Execute one or more child processes.

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>])

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 add_custom_target() and 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.
On Windows platforms, the command line is encoded as a string such that child processes using CommandLineToArgvW will decode the original arguments.

No intermediate shell is used, so shell operators such as > are treated as normal arguments. (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.

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>

Added in version 3.10.

The variable will be set to contain the result of all processes as a semicolon-separated list, 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.

Added in version 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.

ECHO_OUTPUT_VARIABLE, ECHO_ERROR_VARIABLE

Added in version 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>

Added in version 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 CMAKE_EXECUTE_PROCESS_COMMAND_ECHO variable for a way to control the default behavior when this option is not present.

ENCODING <name>

Added in version 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 is the default.
AUTO: Use the current active console's codepage or if that isn't available then use ANSI.
ANSI: Use the ANSI codepage.
OEM: Use the original equipment manufacturer (OEM) code page.
UTF8 or UTF-8: Use the UTF-8 codepage.

Added in version 3.11: Accept UTF-8 spelling for consistency with the UTF-8 RFC naming convention.

COMMAND_ERROR_IS_FATAL <ANY|LAST>

Added in version 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.