1  int open(const char *, int mode);
       2  void close(int fd);
       3  #define O_RDONLY 0
       4  #define O_WRONLY 1
       5  #define O_RDWR 2
       6  #define STDIN 0
       7  
       8  typedef enum {
       9    S_IRWXU
      10    // etc
      11  } mode_t;
      12  
      13  int creat (const char *, mode_t mode);
      14  
      15  void 
      16  test_1 (const char *path)
      17  {
      18      int fd = open (path, O_RDWR); /* { dg-message "\\(1\\) opened here" } */
      19      close (fd); /* { dg-message "\\(2\\) first 'close' here" "event1" } */
      20      close (fd); /* { dg-warning "double 'close' of file descriptor 'fd' \\\[CWE-1341\\\]" "warning" } */
      21      /* { dg-message "\\(3\\) second 'close' here; first 'close' was at \\(2\\)" "event2" { target *-*-* } .-1 } */
      22  }
      23  
      24  void 
      25  test_2 (const char *path)
      26  {
      27      int fd = open (path, O_RDWR); /* { dg-message "\\(1\\) opened here" } */
      28      if (fd < 0) /* { dg-message "\\(2\\) assuming 'fd' is a valid file descriptor \\(>= 0\\)" "event1" } */
      29      /* { dg-message "\\(3\\) following 'false' branch \\(when 'fd >= 0'\\)..." "event2" { target *-*-* } .-1 } */
      30          return;
      31      close (fd); /* { dg-message "\\(4\\) ...to here" "event1" } */
      32      /* { dg-message "\\(5\\) first 'close' here" "event2" { target *-*-* } .-1 } */
      33      close (fd); /* { dg-warning "double 'close' of file descriptor 'fd' \\\[CWE-1341\\\]" "warning" } */
      34      /* {dg-message "\\(6\\) second 'close' here; first was at \\(5\\)" "" { target *-*-* } .-1 } */
      35  }
      36  
      37  void
      38  test_3 ()
      39  {
      40      /* FD 0 is stdin at the entry to "main" and thus read-only, but we have no
      41      guarantees here that it hasn't been closed and then reopened for
      42      writing, so we can't issue a warning */
      43      
      44      int fd = STDIN;
      45      close(fd); /* { dg-message "\\(1\\) first 'close' here" } */
      46      close(fd); /* { dg-warning "double 'close' of file descriptor 'fd' \\\[CWE-1341\\\]" "warning" } */
      47       /* { dg-message "\\(2\\) second 'close' here; first 'close' was at \\(1\\)" "event2" { target *-*-* } .-1 } */
      48  }
      49  
      50  void
      51  test_4 ()
      52  {
      53      int fd = -1;
      54      close(fd);
      55      close(fd);
      56  }
      57  
      58  void
      59  test_5 (const char *path, mode_t mode)
      60  {
      61      int fd = creat (path, mode);
      62      close(fd);
      63      close(fd); /* { dg-warning "double 'close' of file descriptor 'fd' \\\[CWE-1341\\\]" "warning" } */
      64  }