[3/4] support: Add xpthread_mutex_pi_support_monotonic
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Commit Message
Returns true if Priority Inheritance support CLOCK_MONOTONIC.
---
support/Makefile | 1 +
support/xpthread_mutex_pi_support_monotonic.c | 33 +++++++++++++++++++
support/xthread.h | 4 +++
3 files changed, 38 insertions(+)
create mode 100644 support/xpthread_mutex_pi_support_monotonic.c
Comments
* Adhemerval Zanella via Libc-alpha:
> Returns true if Priority Inheritance support CLOCK_MONOTONIC.
In the past, we used support_* interfaces for general checking of system
properties. The x* interfaces are thin wrappers around glibc functions
that terminate the process upon error.
Thanks,
Florian
On 16/08/2021 05:01, Florian Weimer wrote:
> * Adhemerval Zanella via Libc-alpha:
>
>> Returns true if Priority Inheritance support CLOCK_MONOTONIC.
>
> In the past, we used support_* interfaces for general checking of system
> properties. The x* interfaces are thin wrappers around glibc functions
> that terminate the process upon error.
>
> Thanks,
> Florian
>
Fair enough, I will change it.
@@ -179,6 +179,7 @@ libsupport-routines = \
xpthread_sigmask \
xpthread_spin_lock \
xpthread_spin_unlock \
+ xpthread_mutex_pi_support_monotonic \
xraise \
xreadlink \
xrealloc \
new file mode 100644
@@ -0,0 +1,33 @@
+/* Returns whether Priority Inheritance support CLOCK_MONOTONIC.
+ Copyright (C) 2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library 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.
+
+ The GNU C Library 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 the GNU C Library; if not, see
+ <https://www.gnu.org/licenses/>. */
+
+#include <support/xthread.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+
+bool
+xpthread_mutex_pi_support_monotonic (void)
+{
+#ifdef __linux__
+ int r = syscall (__NR_futex, &(unsigned int){0}, 13 /* FUTEX_LOCK_PI2 */,
+ 0, NULL);
+ return r == 0;
+#else
+ return false;
+#endif
+}
@@ -21,6 +21,7 @@
#include <pthread.h>
#include <sys/cdefs.h>
+#include <stdbool.h>
__BEGIN_DECLS
@@ -29,6 +30,9 @@ __BEGIN_DECLS
exit function, so atexit handlers are executed. */
void delayed_exit (int seconds);
+/* Returns true if Priority Inheritance support CLOCK_MONOTONIC. */
+bool xpthread_mutex_pi_support_monotonic (void);
+
/* Terminate the process (with exit status 1) if VALUE is not zero.
In that case, print a failure message to standard output mentioning
FUNCTION. The process is terminated with the exit function, so