show-pbm-1.c

#include <stdio.h>

int main (void)
{
  FILE *f = fopen ("test.pbm", "r");
  char id[42];
  int width, height;
  fscanf (f, "%s", id);  // should be "P4"
  printf ("%s\n", id);
  fscanf (f, "%d", &width);
  fscanf (f, "%d", &height);
  printf ("%d %d\n", width, height);
  return 0;
}