3.1.10 omp_get_nested Function
The omp_get_nested function returns a nonzero value if nested parallelism is enabled and 0 if it is disabled. For more information on nested parallelism, see Section 3.1.9 on page 40. The format is as follows:
#include <omp.h>
int omp_get_nested(void);
If an implementation does not implement nested parallelism, this function always returns 0.