AddCustomCommand.md

• Source code: cmake/modules/PHP/AddCustomCommand.cmake

PHP/AddCustomCommand

Add custom command.

This module is built on top of the CMake add_custom_command and add_custom_target() commands.

A common issue in build systems is the generation of files with the project program itself. Here are two main cases:

• PHP is found on the system: this is the most simple and developer-friendly to use as some files can be generated during the build phase.
• When PHP is not found on the system, ideally the files could be generated after the PHP CLI binary is built in the current project itself. However, this can quickly bring cyclic dependencies between the target at hand, PHP CLI and the generated files. In such case, inconvenience is that two build steps might need to be done in order to generate the entire project once the file has been regenerated.

This module exposes the following function:

php_add_custom_command(
  <unique-symbolic-target-name>
  OUTPUT  ...
  DEPENDS ...
  PHP_COMMAND ...
  [COMMENT <comment>]
  [VERBATIM]
)

Basic usage

It acts similar to add_custom_command() and add_custom_target(), except that when PHP is not found on the system, the DEPENDS argument doesn't add dependencies among targets but instead checks their timestamps manually and executes the PHP_COMMAND only when needed.

# CMakeLists.txt
include(PHP/AddCustomCommand)
php_add_custom_command(
  php_generate_something
  OUTPUT
    list of generated files
  DEPENDS
    list of files or targets that this generation depends on
  PHP_COMMAND
    ${CMAKE_CURRENT_SOURCE_DIR}/generate-something.php
  COMMENT "Generate something"
  VERBATIM
)