Exit codes

Test case reduction tools such as c-reduce typically take an interestingness test as input, which returns 0 for a useful test case or 1 if the test case should be discarded.

The harness can produce two types of errors:

• If the actual shader execution failed, this will manifest as a panic with exit code 101.
• If the shader was successfully executed for all configurations but the outputs differ, the program will exit with code 1.

Otherwise, the program exits normally with code 0.

Normally when using this with a reduction tool to find miscompilations, you will want to discard the shader if the harness returns 0 or 101, since execution failure means that the reduction process probably produced an invalid program. Only the exits with 1 are likely to be interesting.