gl/close-hook.h

   1 /* Hook for making the close() function extensible.
   2    Copyright (C) 2009, 2010 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify it
   5    under the terms of the GNU General Public License as published
   6    by the Free Software Foundation; either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  16
  17
  18 #ifndef CLOSE_HOOK_H
  19 #define CLOSE_HOOK_H
  20
  21 #ifdef __cplusplus
  22 extern "C" {
  23 #endif
  24
  25
  26 /* Currently, this entire code is only needed for the handling of sockets
  27    on native Windows platforms.  */
  28 #if WINDOWS_SOCKETS
  29
  30
  31 /* An element of the list of close hooks.
  32    The fields of this structure are considered private.  */
  33 struct close_hook
  34 {
  35   /* Doubly linked list.  */
  36   struct close_hook *private_next;
  37   struct close_hook *private_prev;
  38   /* Function that treats the types of FD that it knows about and calls
  39      execute_close_hooks (FD, REMAINING_LIST) as a fallback.  */
  40   int (*private_fn) (int fd, const struct close_hook *remaining_list);
  41 };
  42
  43 /* This type of function closes FD, applying special knowledge for the FD
  44    types it knows about, and calls execute_close_hooks (FD, REMAINING_LIST)
  45    for the other FD types.  */
  46 typedef int (*close_hook_fn) (int fd, const struct close_hook *remaining_list);
  47
  48 /* Execute the close hooks in REMAINING_LIST.
  49    Return 0 or -1, like close() would do.  */
  50 extern int execute_close_hooks (int fd, const struct close_hook *remaining_list);
  51
  52 /* Execute all close hooks.
  53    Return 0 or -1, like close() would do.  */
  54 extern int execute_all_close_hooks (int fd);
  55
  56 /* Add a function to the list of close hooks.
  57    The LINK variable points to a piece of memory which is guaranteed to be
  58    accessible until the corresponding call to unregister_close_hook.  */
  59 extern void register_close_hook (close_hook_fn hook, struct close_hook *link);
  60
  61 /* Removes a function from the list of close hooks.  */
  62 extern void unregister_close_hook (struct close_hook *link);
  63
  64
  65 #endif
  66
  67
  68 #ifdef __cplusplus
  69 }
  70 #endif
  71
  72 #endif /* CLOSE_HOOK_H */