antipatie.cpp:5:17: omp.h: No such file or directory antipatie.cpp: In function `void mergeSort(int, int)': antipatie.cpp:19: `omp_get_num_threads' undeclared (first use this function) antipatie.cpp:19: (Each undeclared identifier is reported only once for each function it appears in.) antipatie.cpp:22: warning: ignoring #pragma omp parallel antipatie.cpp:25: warning: ignoring #pragma omp sections antipatie.cpp:28: warning: ignoring #pragma omp section antipatie.cpp:33: warning: ignoring #pragma omp section antipatie.cpp:19: warning: unused variable `int nr_threads' antipatie.cpp: In function `int main()': antipatie.cpp:68: `omp_set_nested' undeclared (first use this function)