none/tests/double_close_range.c

   1 #define _GNU_SOURCE
   2 #include <unistd.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <string.h>
   6 #if defined(__linux__)
   7 #include <linux/close_range.h>
   8 #endif
   9
  10 int main ()
  11 {
  12    // Create a new file descriptor that we immediately close.
  13    // This is of course fine.
  14    int fd = dup (2);
  15    if (fd != -1){
  16       fprintf(stderr, "close fd %d\n", fd);
  17       close (fd);
  18    }
  19
  20    // Shouldn't warn, we are closing everything
  21    // This is a special case for close_range if the last
  22    // argument is ~0U (infinity).
  23    fprintf(stderr, "Closing range (%d, %d).\n", fd, ~0U);
  24    close_range(fd, ~0U, 0);
  25
  26    int fd5 = dup2(1, 5);
  27    int fd7 = dup2(2, 7);
  28    fprintf(stderr, "Closing range (%d, %d).\n", fd5, fd7);
  29    close_range(5, 7, 0);
  30
  31    // Should warn, we close a small range
  32    fprintf(stderr, "Double closing range (%d, %d).\n", fd5, fd7);
  33    close_range(5, 7, 0);
  34
  35    return 0;
  36 }