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Hash :
19adc7a2
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Date :
2025-09-09T12:50:18
Remove support for OSF/1. * all-modules: Update comments. * build-aux/install-reloc: Likewise. * gnulib-tool: Likewise. * gnulib-tool.py: Likewise. * gnulib-tool.sh: Likewise. * lib/calloc.c: Likewise. * lib/euidaccess.c: Likewise. * lib/fbufmode.c: Likewise. * lib/fflush.c: Likewise. * lib/fpending.c: Likewise. * lib/fpurge.c: Likewise. * lib/freadable.c: Likewise. * lib/freadahead.c: Likewise. * lib/freading.c: Likewise. * lib/freadptr.c: Likewise. * lib/freadseek.c: Likewise. * lib/fseeko.c: Likewise. * lib/fseterr.c: Likewise. * lib/fwritable.c: Likewise. * lib/fwriting.c: Likewise. * lib/get-permissions.c: Likewise. * lib/get-rusage-as.c: Likewise. * lib/getdomainname.c: Likewise. * lib/getpass.c: Likewise. * lib/glthread/spin.c: Likewise. * lib/idpriv-drop.c: Likewise. * lib/idpriv-droptemp.c: Likewise. * lib/log10l.c: Likewise. * lib/login_tty.c: Likewise. * lib/minmax.h: Likewise. * lib/mountlist.c: Likewise. * lib/netdb.in.h: Likewise. * lib/nproc.c: Likewise. * lib/passfd.c: Likewise. * lib/posix_openpt.c: Likewise. * lib/resource-ext.h: Likewise. * lib/safe-read.h: Likewise. * lib/safe-write.h: Likewise. * lib/stdint.in.h: Likewise. * lib/stdio.in.h: Likewise. * lib/string.in.h: Likewise. * lib/sys-limits.h: Likewise. * lib/termcap.h: Likewise. * lib/terminfo.h: Likewise. * lib/ttyname_r.c: Likewise. * lib/vasnprintf.c: Likewise. * lib/wait-process.c: Likewise. * m4/fmal.m4: Likewise. * m4/getdomainname.m4: Likewise. * m4/getopt.m4: Likewise. * m4/hypot.m4: Likewise. * m4/hypotf.m4: Likewise. * m4/hypotl.m4: Likewise. * m4/iconv.m4: Likewise. * m4/iconv_open-utf.m4: Likewise. * m4/imaxabs.m4: Likewise. * m4/imaxdiv.m4: Likewise. * m4/largefile.m4: Likewise. * m4/link-follow.m4: Likewise. * m4/locale-fr.m4: Likewise. * m4/locale-ja.m4: Likewise. * m4/locale_h.m4: Likewise. * m4/lock.m4: Likewise. * m4/log10l.m4: Likewise. * m4/mkstemp.m4: Likewise. * m4/mmap-anon.m4: Likewise. * m4/modf.m4: Likewise. * m4/modff.m4: Likewise. * m4/modfl.m4: Likewise. * m4/semaphore.m4: Likewise. * m4/socklen.m4: Likewise. * m4/strerror_r.m4: Likewise. * m4/terminfo.m4: Likewise. * m4/wcwidth.m4: Likewise. * posix-modules: Likewise. * tests/havelib/README: Likewise. * tests/init.sh: Likewise. * tests/socket-client.h: Likewise. * tests/socket-server.h: Likewise. * tests/test-echo.sh: Likewise. * tests/test-nonblocking-socket.h: Likewise. * tests/test-strtod.h: Likewise. * tests/test-strtof.h: Likewise.
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/* Spin locks in multithreaded situations.
Copyright (C) 2020-2025 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>, 2020. */
#include <config.h>
/* Specification. */
#include "glthread/spin.h"
#include <errno.h>
#if defined _AIX
# include <sys/atomic_op.h>
#endif
#if 0x590 <= __SUNPRO_C && __STDC__
# define asm __asm
#endif
#if defined _WIN32 && !defined __CYGWIN__
/* Use Windows threads. */
/* All definitions are inline in glthread/spin.h. */
#else
/* We don't use semaphores (although sem_post() is allowed in signal handlers),
because it would require to link with -lrt on HP-UX 11, Solaris 10, and also
because on macOS only named semaphores work.
We don't use the C11 <stdatomic.h> (available in GCC >= 4.9) because it would
require to link with -latomic. */
# if (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 7) \
|| __clang_major__ > 3 || (__clang_major__ == 3 && __clang_minor__ >= 1)) \
&& !defined __ibmxl__
/* Use GCC built-ins (available in GCC >= 4.7 and clang >= 3.1) that operate on
the first byte of the lock.
Documentation:
<https://gcc.gnu.org/onlinedocs/gcc-4.7.0/gcc/_005f_005fatomic-Builtins.html>
*/
# if 1
/* An implementation that verifies the unlocks. */
void
glthread_spinlock_init (gl_spinlock_t *lock)
{
__atomic_store_n (lock, 0, __ATOMIC_SEQ_CST);
}
void
glthread_spinlock_lock (gl_spinlock_t *lock)
{
/* Wait until *lock becomes 0, then replace it with 1. */
gl_spinlock_t zero;
while (!(zero = 0,
__atomic_compare_exchange_n (lock, &zero, 1, false,
__ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)))
;
}
int
glthread_spinlock_unlock (gl_spinlock_t *lock)
{
/* If *lock is 1, then replace it with 0. */
gl_spinlock_t one = 1;
if (!__atomic_compare_exchange_n (lock, &one, 0, false,
__ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST))
return EINVAL;
return 0;
}
# else
/* An implementation that is a little bit more optimized, but does not verify
the unlocks. */
void
glthread_spinlock_init (gl_spinlock_t *lock)
{
__atomic_clear (lock, __ATOMIC_SEQ_CST);
}
void
glthread_spinlock_lock (gl_spinlock_t *lock)
{
while (__atomic_test_and_set (lock, __ATOMIC_SEQ_CST))
;
}
int
glthread_spinlock_unlock (gl_spinlock_t *lock)
{
__atomic_clear (lock, __ATOMIC_SEQ_CST);
return 0;
}
# endif
# elif (((__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)) \
|| __clang_major__ >= 3) \
&& HAVE_ATOMIC_COMPARE_AND_SWAP_GCC41)
/* Use GCC built-ins (available on many platforms with GCC >= 4.1 or
clang >= 3.0).
Documentation:
<https://gcc.gnu.org/onlinedocs/gcc-4.1.2/gcc/Atomic-Builtins.html> */
void
glthread_spinlock_init (gl_spinlock_t *lock)
{
volatile unsigned int *vp = lock;
*vp = 0;
__sync_synchronize ();
}
void
glthread_spinlock_lock (gl_spinlock_t *lock)
{
/* Wait until *lock becomes 0, then replace it with 1. */
while (__sync_val_compare_and_swap (lock, 0, 1) != 0)
;
}
int
glthread_spinlock_unlock (gl_spinlock_t *lock)
{
/* If *lock is 1, then replace it with 0. */
if (__sync_val_compare_and_swap (lock, 1, 0) != 1)
return EINVAL;
return 0;
}
# elif defined _AIX
/* AIX */
void
glthread_spinlock_init (gl_spinlock_t *lock)
{
atomic_p vp = (int *) lock;
_clear_lock (vp, 0);
}
void
glthread_spinlock_lock (gl_spinlock_t *lock)
{
atomic_p vp = (int *) lock;
while (_check_lock (vp, 0, 1))
;
}
int
glthread_spinlock_unlock (gl_spinlock_t *lock)
{
atomic_p vp = (int *) lock;
if (_check_lock (vp, 1, 0))
return EINVAL;
return 0;
}
# elif ((defined __GNUC__ || defined __clang__ || defined __SUNPRO_C) && (defined __sparc || defined __i386 || defined __x86_64__)) || (defined __TINYC__ && (defined __i386 || defined __x86_64__))
/* For older versions of GCC or clang, use inline assembly.
GCC, clang, and the Oracle Studio C 12 compiler understand GCC's extended
asm syntax, but the plain Oracle Studio C 11 compiler understands only
simple asm. */
/* An implementation that verifies the unlocks. */
static void
memory_barrier (void)
{
# if defined __GNUC__ || defined __clang__ || __SUNPRO_C >= 0x590 || defined __TINYC__
# if defined __i386 || defined __x86_64__
# if defined __TINYC__ && defined __i386
/* Cannot use the SSE instruction "mfence" with this compiler. */
asm volatile ("lock orl $0,(%esp)");
# else
asm volatile ("mfence");
# endif
# endif
# if defined __sparc
asm volatile ("membar 2");
# endif
# else
# if defined __i386 || defined __x86_64__
asm ("mfence");
# endif
# if defined __sparc
asm ("membar 2");
# endif
# endif
}
/* Store NEWVAL in *VP if the old value *VP is == CMP.
Return the old value. */
static unsigned int
atomic_compare_and_swap (volatile unsigned int *vp, unsigned int cmp,
unsigned int newval)
{
# if defined __GNUC__ || defined __clang__ || __SUNPRO_C >= 0x590 || defined __TINYC__
unsigned int oldval;
# if defined __i386 || defined __x86_64__
asm volatile (" lock\n cmpxchgl %3,(%1)"
: "=a" (oldval) : "r" (vp), "a" (cmp), "r" (newval) : "memory");
# endif
# if defined __sparc
asm volatile (" cas [%1],%2,%3\n"
" mov %3,%0"
: "=r" (oldval) : "r" (vp), "r" (cmp), "r" (newval) : "memory");
# endif
return oldval;
# else /* __SUNPRO_C */
# if defined __x86_64__
asm (" movl %esi,%eax\n"
" lock\n cmpxchgl %edx,(%rdi)");
# elif defined __i386
asm (" movl 16(%ebp),%ecx\n"
" movl 12(%ebp),%eax\n"
" movl 8(%ebp),%edx\n"
" lock\n cmpxchgl %ecx,(%edx)");
# endif
# if defined __sparc
asm (" cas [%i0],%i1,%i2\n"
" mov %i2,%i0");
# endif
# endif
}
void
glthread_spinlock_init (gl_spinlock_t *lock)
{
volatile unsigned int *vp = lock;
*vp = 0;
memory_barrier ();
}
void
glthread_spinlock_lock (gl_spinlock_t *lock)
{
volatile unsigned int *vp = lock;
while (atomic_compare_and_swap (vp, 0, 1) != 0)
;
}
int
glthread_spinlock_unlock (gl_spinlock_t *lock)
{
volatile unsigned int *vp = lock;
if (atomic_compare_and_swap (vp, 1, 0) != 1)
return EINVAL;
return 0;
}
# else
/* Fallback code. It has some race conditions. */
void
glthread_spinlock_init (gl_spinlock_t *lock)
{
volatile unsigned int *vp = lock;
*vp = 0;
}
void
glthread_spinlock_lock (gl_spinlock_t *lock)
{
volatile unsigned int *vp = lock;
while (*vp)
;
*vp = 1;
}
int
glthread_spinlock_unlock (gl_spinlock_t *lock)
{
volatile unsigned int *vp = lock;
*vp = 0;
return 0;
}
# endif
void
glthread_spinlock_destroy (gl_spinlock_t *lock)
{
}
#endif