[cmake-developers] FindBacktrace.cmake

[Brad King]

On 07/08/2013 05:51 PM, Vadim Zhukov wrote:
> I'm not sure whether resetting CMAKE_REQUIRED_* is the desired
> behavior. The example in the CMakePushCheckState.cmake documentation
> tells the opposite, and I think that appending values have a point by
> adding some sort of a flexibility for writers of other CMake project
> files and other CMake modules. Also, I see the same logic (append
> instead of rewrite) is used in other CMake modules (in KDE at least,
> where CMakePushCheckState.cmake did came from).
> 
> And if CMAKE_REQUIRED_* should be generally reset within module, then
> I propose adding a third macro in CMakePushCheckState.cmake, say,
> cmake_reset_check_state(), which will do this.
> 
> I'm adding Alexander Neundorf to the thread to make things more clear,
> as he developed CMakePushCheckState.cmake module. Alexander, could
> you, please, explain the way CMakePushCheckState macros should be
> used?

I would like Alex's opinion on this, but we must either use
CMAKE_REQUIRED_* to report the results (as you did originally)
or not use the caller's CMAKE_REQUIRED_* to perform the test.
Otherwise the results will not be consistent.

We have never (intentionally) defined CMAKE_REQUIRED_* as the
input to a _find_ module before, only to _check_ macros.  The
check state stack module helps a project handle its own check
accumulation and AFAIK is not meant as an API between a project
and CMake find modules.

It looks like a few find modules already use check macros and
do not pay any attention to whether CMAKE_REQUIRED_* is defined.
These may also need to be cleaned up based on the results of this
discussion.

-Brad