Update.
[glibc.git] / stdlib / atexit.c
blob7205f50dc0e10b92497e515b83629fe3cedc297d
1 /* Copyright (C) 1991, 1996 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Library General Public License as
6 published by the Free Software Foundation; either version 2 of the
7 License, or (at your option) any later version.
9 The GNU C Library 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 Library General Public License for more details.
14 You should have received a copy of the GNU Library General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If not,
16 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 Boston, MA 02111-1307, USA. */
19 #include <bits/libc-lock.h>
20 #include <stdlib.h>
21 #include "exit.h"
24 /* Register FUNC to be executed by `exit'. */
25 int
26 atexit (void (*func) (void))
28 struct exit_function *new = __new_exitfn ();
30 if (new == NULL)
31 return -1;
33 new->flavor = ef_at;
34 new->func.at = func;
35 return 0;
39 /* We change global data, so we need locking. */
40 __libc_lock_define_initialized (static, lock)
43 static struct exit_function_list fnlist = { NULL, 0, };
44 struct exit_function_list *__exit_funcs = &fnlist;
46 struct exit_function *
47 __new_exitfn (void)
49 struct exit_function_list *l;
50 size_t i = 0;
52 __libc_lock_lock (lock);
54 for (l = __exit_funcs; l != NULL; l = l->next)
56 for (i = 0; i < l->idx; ++i)
57 if (l->fns[i].flavor == ef_free)
58 break;
59 if (i < l->idx)
60 break;
62 if (l->idx < sizeof (l->fns) / sizeof (l->fns[0]))
64 i = l->idx++;
65 break;
69 if (l == NULL)
71 l = (struct exit_function_list *)
72 malloc (sizeof (struct exit_function_list));
73 if (l != NULL)
75 l->next = __exit_funcs;
76 __exit_funcs = l;
78 l->idx = 1;
79 i = 0;
83 /* Mark entry as used, but we don't know the flavor now. */
84 if (l != NULL)
85 l->fns[i].flavor = ef_us;
87 __libc_lock_unlock (lock);
89 return l == NULL ? NULL : &l->fns[i];