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FUTEX_TRYLOCK_PI(2const) — Linux manual page

FUTEX_TRYLOCK_PI(2const)FUTEX_TRYLOCK_PI(2const)

NAME        top

       FUTEX_TRYLOCK_PI - try to lock a priority-inheritance futex

LIBRARY        top

       Standard C library (libc,-lc)

SYNOPSIS        top

#include <linux/futex.h>/* Definition ofFUTEX_*constants */#include <sys/syscall.h>/* Definition ofSYS_*constants */#include <unistd.h>long syscall(SYS_futex, uint32_t *uaddr, FUTEX_TRYLOCK_PI);

DESCRIPTION        top

       This operation tries to acquire the lock atuaddr.  It is invoked       when a user-space atomic acquire did not succeed because the futex       word was not 0.       Because the kernel has access to more state information than user       space, acquisition of the lock might succeed if performed by the       kernel in cases where the futex word (i.e., the state information       accessible to use-space) contains stale state (FUTEX_WAITERS       and/orFUTEX_OWNER_DIED).  This can happen when the owner of the       futex died.  User space cannot handle this condition in a race-       free manner, but the kernel can fix this up and acquire the futex.

RETURN VALUE        top

       On error, -1 is returned, anderrno is set to indicate the error.       On success,FUTEX_TRYLOCK_PIReturns 0 if the futex was       successfully locked.

ERRORS        top

       Seefutex(2).EAGAINThe futex owner thread ID ofuaddr is about to exit, but              has not yet handled the internal state cleanup.  Try again.EDEADLK              The futex word atuaddr is already locked by the caller.EINVALThe kernel detected an inconsistency between the user-space              state atuaddr and the kernel state.  This indicates either              state corruption or that the kernel found a waiter onuaddr              which is waiting viaFUTEX_WAIT(2const) orFUTEX_WAIT_BITSET(2const).ENOMEMThe kernel could not allocate memory to hold state              information.ENOSYSA 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.EPERMThe caller is not allowed to attach itself to the futex atuaddr.  (This may be caused by a state corruption in user              space.)ESRCHThe thread ID in the futex word atuaddr does not exist.

STANDARDS        top

       Linux.

HISTORY        top

       Linux 2.6.18.

SEE ALSO        top

futex(2)

COLOPHON        top

       This page is part of theman-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       fetched from       ⟨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-       to-date source for the page, or you have corrections or       improvements to the information in this COLOPHON (which isnot       part of the original manual page), send a mail to       man-pages@man7.orgLinux man-pages 6.15            2025-05-30FUTEX_TRYLOCK_PI(2const)

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