FUTEX_TRYLOCK_PI(2const)                              FUTEX_TRYLOCK_PI(2const)

NAME
       FUTEX_TRYLOCK_PI - try to lock a priority-inheritance futex

LIBRARY
       Standard C library (libc, -lc)

SYNOPSIS
       #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_TRYLOCK_PI);

DESCRIPTION
       This operation tries to acquire the lock at uaddr.  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/or
       FUTEX_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
       On error, -1 is returned, and errno is set to indicate the error.

       On success, FUTEX_TRYLOCK_PI Returns 0 if the futex was successfully
       locked.

ERRORS
       See futex(2).

       EAGAIN The futex owner thread ID of uaddr is about to exit, but has not
              yet handled the internal state cleanup.  Try again.

       EDEADLK
              The futex word at uaddr is already locked by the caller.

       EINVAL The kernel detected an inconsistency between the user-space
              state at uaddr and the kernel state.  This indicates either
              state corruption or that the kernel found a waiter on uaddr
              which is waiting via FUTEX_WAIT(2const) or
              FUTEX_WAIT_BITSET(2const).

       ENOMEM The kernel could not allocate memory to hold state information.

       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.

       EPERM  The caller is not allowed to attach itself to the futex at
              uaddr.  (This may be caused by a state corruption in user
              space.)

       ESRCH  The thread ID in the futex word at uaddr does not exist.

STANDARDS
       Linux.

HISTORY
       Linux 2.6.18.

SEE ALSO
       futex(2)

Linux man-pages 6.15              2025-05-30          FUTEX_TRYLOCK_PI(2const)