diff options
author | Jörg Frings-Fürst <debian@jff.email> | 2025-03-22 18:00:25 +0100 |
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committer | Jörg Frings-Fürst <debian@jff.email> | 2025-03-22 18:00:25 +0100 |
commit | 0737819efdd0bae112d16d874cac7e747e43cd08 (patch) | |
tree | 98a9ac84f7f347ae530c14852c68870682f3d04c /lib/glthread/once.c | |
parent | 163a663518f33bab48b28431972e580b366b4d49 (diff) | |
parent | e670957a8693f860cf7d77fed4ce6b4b056a8083 (diff) |
Merge branch 'release/debian/1.3-1'debian/1.3-1
Diffstat (limited to 'lib/glthread/once.c')
-rw-r--r-- | lib/glthread/once.c | 80 |
1 files changed, 80 insertions, 0 deletions
diff --git a/lib/glthread/once.c b/lib/glthread/once.c new file mode 100644 index 00000000..869ba3ba --- /dev/null +++ b/lib/glthread/once.c @@ -0,0 +1,80 @@ +/* Once-only initialization in multithreaded situations. + Copyright (C) 2005-2024 Free Software Foundation, Inc. + + This file is free software: you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation; either version 2.1 of the + License, or (at your option) any later version. + + This file is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +/* Written by Bruno Haible <bruno@clisp.org>, 2005. + Based on GCC's gthr-posix.h, gthr-posix95.h. */ + +#include <config.h> + +#include "glthread/once.h" + +/* ========================================================================= */ + +#if USE_ISOC_THREADS || USE_ISOC_AND_POSIX_THREADS + +#endif + +/* ========================================================================= */ + +#if USE_POSIX_THREADS + +static const pthread_once_t fresh_once = PTHREAD_ONCE_INIT; + +int +glthread_once_singlethreaded (pthread_once_t *once_control) +{ + /* We don't know whether pthread_once_t is an integer type, a floating-point + type, a pointer type, or a structure type. */ + char *firstbyte = (char *)once_control; + if (*firstbyte == *(const char *)&fresh_once) + { + /* First time use of once_control. Invert the first byte. */ + *firstbyte = ~ *(const char *)&fresh_once; + return 1; + } + else + return 0; +} + +# if !(PTHREAD_IN_USE_DETECTION_HARD || USE_POSIX_THREADS_WEAK) + +int +glthread_once_multithreaded (pthread_once_t *once_control, + void (*init_function) (void)) +{ + int err = pthread_once (once_control, init_function); + if (err == ENOSYS) + { + /* This happens on FreeBSD 11: The pthread_once function in libc returns + ENOSYS. */ + if (glthread_once_singlethreaded (once_control)) + init_function (); + return 0; + } + return err; +} + +# endif + +#endif + +/* ========================================================================= */ + +#if USE_WINDOWS_THREADS + +#endif + +/* ========================================================================= */ |