Build events

add_custom_command has a form which can be used to add a custom command to a target such as a library or executable which runs either just before or just after the target is built.

For example, the following post build event copies the executable to some folder:

add_executable(myprog main.c)

add_custom_command(
    TARGET myprog
    POST_BUILD
    COMMAND ${CMAKE_COMMAND} -E make_directory ${PROJECT_BINARY_DIR}
    COMMAND ${CMAKE_COMMAND} -E copy $<TARGET_FILE:myprog> ${PROJECT_BINARY_DIR}/.)

When the command will happen is determined by which of the following is specified:

• PRE_BUILD : On Visual Studio Generators, run before any other rules are executed within the target. On other generators, run just before PRE_LINK commands.
• PRE_LINK : Run after sources have been compiled but before linking the binary or running the librarian or archiver tool of a static library. This is not defined for targets created by the add_custom_target() command.
• POST_BUILD : Run after all other rules within the target have been executed.

There is a restriction which is imposed: The target in the TARGET signature of add_custom_command() must exist and must be defined in the current directory. This usually means you will add the build event command in the same file that adds the target to which it refers.