6.4.2 Guidelines for Test Programs

Test programs should not write anything to the standard output. They should return 0 if the test succeeds, nonzero otherwise, so that success can be distinguished easily from a core dump or other failure; segmentation violations and other failures produce a nonzero exit status. Test programs should exit, not return, from main, because on some systems (old Suns, at least) the argument to return in main is ignored.

Test programs can use #if or #ifdef to check the values of preprocessor macros defined by tests that have already run. For example, if you call AC_HEADER_STDC, then later on in `configure.ac' you can have a test program that includes an ANSI C header file conditionally:

#if STDC_HEADERS # include <stdlib.h> #endif

If a test program needs to use or create a data file, give it a name that starts with `conftest', such as `conftest.data'. The configure script cleans up by running `rm -rf conftest*' after running test programs and if the script is interrupted.