futex_wait.md

mx_futex_wait

NAME

futex_wait - Wait on a futex.

SYNOPSIS

#include <magenta/syscalls.h>

mx_status_t mx_futex_wait(mx_futex_t* value_ptr, int current_value,
                          mx_time_t deadline);

DESCRIPTION

Waiting on a futex (or acquiring it) causes a thread to sleep until the futex is made available by a call to mx_futex_wake. Optionally, the thread can also be woken up after the deadline (with respect to MX_CLOCK_MONOTONIC) passes.

RETURN VALUE

futex_wait() returns MX_OK on success.

ERRORS

MX_ERR_INVALID_ARGS value_ptr is not a valid userspace pointer, or value_ptr is not aligned.

MX_ERR_BAD_STATE current_value does not match the value at value_ptr.

MX_ERR_TIMED_OUT The thread was not woken before deadline passed.

SEE ALSO

futex_requeue, futex_wake.