# CMakePushCheckState

This module defines three macros: `CMAKE_PUSH_CHECK_STATE()` `CMAKE_POP_CHECK_STATE()` and `CMAKE_RESET_CHECK_STATE()` These macros can be used to save, restore and reset (i.e., clear contents) the state of the variables `CMAKE_REQUIRED_FLAGS`, `CMAKE_REQUIRED_DEFINITIONS`, `CMAKE_REQUIRED_LINK_OPTIONS`, `CMAKE_REQUIRED_LIBRARIES`, `CMAKE_REQUIRED_LINK_DIRECTORIES`, `CMAKE_REQUIRED_INCLUDES` and `CMAKE_EXTRA_INCLUDE_FILES` used by the various Check-files coming with CMake, like e.g. `check_function_exists()` etc. The variable contents are pushed on a stack, pushing multiple times is supported. This is useful e.g. when executing such tests in a Find-module, where they have to be set, but after the Find-module has been executed they should have the same value as they had before.

`CMAKE_PUSH_CHECK_STATE()` macro receives optional argument `RESET`. Whether it's specified, `CMAKE_PUSH_CHECK_STATE()` will set all `CMAKE_REQUIRED_*` variables to empty values, same as `CMAKE_RESET_CHECK_STATE()` call will do.

Usage:

    cmake_push_check_state(RESET)
    set(CMAKE_REQUIRED_DEFINITIONS -DSOME_MORE_DEF)
    check_function_exists(...)
    cmake_reset_check_state()
    set(CMAKE_REQUIRED_DEFINITIONS -DANOTHER_DEF)
    check_function_exists(...)
    cmake_pop_check_state()