是否可以在一个程序的多个文件中使用OpenMP指令？

#include <stdio.h>
#include <stdlib.h>
#include <omp.h>

void inner(int n);

int main(int argc, char **argv) {
    int n=15;

    #pragma omp parallel shared(n) num_threads(4)
    {
        inner(n);
    }

    return 0;
}

#include <omp.h>
#include <stdio.h>

void inner(int n) {
    int thread = omp_get_thread_num();
    printf(\"%3d: got %d\\n\", thread, n);

    #pragma omp for
    for  (int i=0;i<n;i++) {
        int newthread=omp_get_thread_num();
        printf(\"%3d: doing iter %d.\\n\",newthread,i);
    }
}

$ make
gcc -fopenmp -std=c99   -c -o outer.o outer.c
gcc -fopenmp -std=c99   -c -o inner.o inner.c
gcc -o nested outer.o inner.o -fopenmp -std=c99 -lgomp    
$ ./nested 
  3: got 15
  3: doing iter 12.
  3: doing iter 13.
  3: doing iter 14.
  0: got 15
  0: doing iter 0.
  0: doing iter 1.
  0: doing iter 2.
  0: doing iter 3.
  1: got 15
  1: doing iter 4.
  1: doing iter 5.
  1: doing iter 6.
  1: doing iter 7.
  2: got 15
  2: doing iter 8.
  2: doing iter 9.
  2: doing iter 10.
  2: doing iter 11.

    int n=15;

    #pragma omp parallel shared(n) num_threads(4)
    {
        int thread = omp_get_thread_num();
        printf(\"%3d: got %d\\n\", thread, n);

        #pragma omp for
        for  (int i=0;i<n;i++) {
            int newthread=omp_get_thread_num();
            printf(\"%3d: doing iter %d.\\n\",newthread,i);
        }
    }