Add GLIBC_2.9 version tag for libutil.
[glibc/history.git] / stdlib / cxa_atexit.c
blob3bdf871e53adeb2bffa67240aee976e0f2d39eb5
1 /* Copyright (C) 1999, 2001, 2002, 2005, 2006 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 Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the 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 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, write to the Free
16 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
17 02111-1307 USA. */
19 #include <assert.h>
20 #include <stdlib.h>
22 #include <bits/libc-lock.h>
23 #include "exit.h"
24 #include <atomic.h>
25 #include <sysdep.h>
27 #undef __cxa_atexit
29 /* Register a function to be called by exit or when a shared library
30 is unloaded. This function is only called from code generated by
31 the C++ compiler. */
32 int
33 __cxa_atexit (void (*func) (void *), void *arg, void *d)
35 struct exit_function *new = __new_exitfn ();
37 if (new == NULL)
38 return -1;
40 #ifdef PTR_MANGLE
41 PTR_MANGLE (func);
42 #endif
43 new->func.cxa.fn = (void (*) (void *, int)) func;
44 new->func.cxa.arg = arg;
45 new->func.cxa.dso_handle = d;
46 atomic_write_barrier ();
47 new->flavor = ef_cxa;
48 return 0;
50 INTDEF(__cxa_atexit)
53 /* We change global data, so we need locking. */
54 __libc_lock_define_initialized (static, lock)
57 static struct exit_function_list initial;
58 struct exit_function_list *__exit_funcs = &initial;
59 uint64_t __new_exitfn_called;
61 struct exit_function *
62 __new_exitfn (void)
64 struct exit_function_list *p = NULL;
65 struct exit_function_list *l;
66 struct exit_function *r = NULL;
67 size_t i = 0;
69 __libc_lock_lock (lock);
71 for (l = __exit_funcs; l != NULL; p = l, l = l->next)
73 for (i = l->idx; i > 0; --i)
74 if (l->fns[i - 1].flavor != ef_free)
75 break;
77 if (i > 0)
78 break;
80 /* This block is completely unused. */
81 l->idx = 0;
84 if (l == NULL || i == sizeof (l->fns) / sizeof (l->fns[0]))
86 /* The last entry in a block is used. Use the first entry in
87 the previous block if it exists. Otherwise create a new one. */
88 if (p == NULL)
90 assert (l != NULL);
91 p = (struct exit_function_list *)
92 calloc (1, sizeof (struct exit_function_list));
93 if (p != NULL)
95 p->next = __exit_funcs;
96 __exit_funcs = p;
100 if (p != NULL)
102 r = &p->fns[0];
103 p->idx = 1;
106 else
108 /* There is more room in the block. */
109 r = &l->fns[i];
110 l->idx = i + 1;
113 /* Mark entry as used, but we don't know the flavor now. */
114 if (r != NULL)
116 r->flavor = ef_us;
117 ++__new_exitfn_called;
120 __libc_lock_unlock (lock);
122 return r;