Making a Unix-specific CMake procedure cross-platform

Question

I've written a small CMake module for, well, it doesn't matter what for. The point is that it acts as follows:

• When the appropriate CMake function is invoked, a shell script with relative path scripts/whatever.sh (under the project directory) is invoked.
• The shell script cat's a 'here-file' containing a C program to the C compiler found by CMake (with fallback to cc)
• The program is compiled, linked and run, producing some text
• The output text is saved as a CMake variable

This is relatively robust on Unix-like systems, where cat and bash are available and when the path separator is /. (There may be other assumptions I'm ignoring.) But - I want this to work on Windows, and other systems as well. How do I go about doing this?

Notes:

• In case it's relevant: The shell script and the CMake module.
• I can use C++ instead of C if that helps.

Answer 1

You may use CMake scripts for being cross-platform. Many things may be performed directly in CMakeLists.txt and scripts included from it:

• "Here in document" support in CMake is not the best, but it is not very difficult to store text of a small program into a CMake variable.

• execute_process is able to run external programs from CMake script and store output of that program in CMake variable. Also, try_compile or try_run may be useful in some scenarios.