1 #include 
     
       2 #include 
      
        3 #include 
       
         4 #include 
        
          5 int main(int argc, char **argv) 6 { 7     const char A = 'a'; 8     FILE *fp     = NULL; 9     char * p     = NULL;10     long i       = 0L;11     long size    = 0L;12     time_t start = 0L;13     time_t end   = 0L;14     struct timeval tv_start = {
   0};15     struct timeval tv_end   = {
   0};    16     p = *++argv;17     if (p == NULL) {18         printf("Input file size by mb, please. SIZE(mb) = ");19         scanf("%d", &size);20     }21     if (size == 0L) {22         size = atoi(p);23     }24     fp = fopen("dump.dat", "w");25     26     if(fp == NULL) 27     {28         perror("failed to open dump.dat");29         return EXIT_FAILURE;30     }31     timerclear(&tv_start);32     timerclear(&tv_end);33     /// time(&start);34     gettimeofday(&tv_start, NULL);35     for (i = 0; i < 1024 * 1024 * size; i++)36     {37         fputc(A, fp);38     }39     gettimeofday(&tv_end, NULL);40     /// time(&end);41     42     start = tv_start.tv_sec * 1000000 + tv_start.tv_usec;43     end = tv_end.tv_sec * 1000000 + tv_end.tv_usec;44     printf("Wrote %d bytes. fclose(fp) %s./n", i, fclose(fp) == 0 ? "succeeded" : "failed");45     printf("TIME = %d.%3d s./n", (end - start)/1000000, ((end - start)/1000)%1000);46     return EXIT_SUCCESS;47 }