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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
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FUTEX_WAIT_REQUEUE_PI(2const) FUTEX_WAIT_REQUEUE_PI(2const)
FUTEX_WAIT_REQUEUE_PI - wait on a non-PI futex, and potentially be
requeued onto a PI futex
Standard C library (libc, -lc)
#include <linux/futex.h> /* Definition of FUTEX_* constants */
#include <sys/syscall.h> /* Definition of SYS_* constants */
#include <unistd.h>
long syscall(SYS_futex, uint32_t *uaddr, FUTEX_WAIT_REQUEUE_PI,
uint32_t val,
const struct timespec *timeout,
uint32_t *uaddr2);
Wait on a non-PI futex at uaddr and potentially be requeued (via a
FUTEX_CMP_REQUEUE_PI(2const) operation in another task) onto a PI
futex at uaddr2. The wait operation on uaddr is the same as for
FUTEX_WAIT(2const).
The waiter can be removed from the wait on uaddr without
requeueing on uaddr2 via a FUTEX_WAKE(2const) operation in another
task. In this case, the FUTEX_WAIT_REQUEUE_PI operation fails
with the error EAGAIN.
If timeout is not NULL, the structure it points to specifies an
absolute timeout for the wait operation. If timeout is NULL, the
operation can block indefinitely.
On error, -1 is returned, and errno is set to indicate the error.
On success, FUTEX_WAIT_REQUEUE_PI returns 0 if the caller was
successfully requeued to the futex for the futex word at uaddr2.
See futex(2).
EAGAIN The value pointed to by uaddr was not equal to the expected
value val at the time of the call.
Note: on Linux, the symbolic names EAGAIN and EWOULDBLOCK
(both of which appear in different parts of the kernel
futex code) have the same value.
EFAULT uaddr2 or timeout did not point to a valid user-space
address.
EINVAL The supplied timeout argument was invalid (tv_sec was less
than zero, or tv_nsec was not less than 1,000,000,000).
EINVAL uaddr2 does not point to a valid object—that is, the
address is not four-byte-aligned.
ENOSYS A run-time check determined that the operation is not
available. The PI-futex operations are not implemented on
all architectures and are not supported on some CPU
variants.
ETIMEDOUT
The timeout expired before the operation completed.
Linux.
Linux 2.6.31.
futex(2)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.15.tar.gz
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⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-08-11. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
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part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.15 2025-05-30 FUTEX_WAIT_REQUEUE_PI(2const)
Pages that refer to this page: futex(2), FUTEX_CMP_REQUEUE_PI(2const)
Copyright and license for this manual page
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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