A.2 Specifying Conditional Compilation

The following examples illustrate the use of conditional compilation using the OpenMP macro _OPENMP (Section 2.2 on page 8). With OpenMP compilation, the _OPENMP macro becomes defined.

# ifdef _OPENMP 
    printf_s("Compiled by an OpenMP-compliant implementation.\n");
# endif

The defined preprocessor operator allows more than one macro to be tested in a single directive.

# if defined(_OPENMP) && defined(VERBOSE)
    printf_s("Compiled by an OpenMP-compliant implementation.\n");
# endif