EVENTFD_CTX_READ(9) Events based on file descripto EVENTFD_CTX_READ(9)NAMEeventfd_ctx_read - Reads the eventfd counter or wait if it is zero.
SYNOPSIS
ssize_t eventfd_ctx_read(struct eventfd_ctx * ctx, int no_wait,
__u64 * cnt);
ARGUMENTS
ctx
[in] Pointer to eventfd context.
no_wait
[in] Different from zero if the operation should not block.
cnt
[out] Pointer to the 64-bit counter value.
DESCRIPTION
Returns 0 if successful, or the following error codes:
-EAGAIN : The operation would have blocked but no_wait was non-zero.
-ERESTARTSYS : A signal interrupted the wait operation.
If no_wait is zero, the function might sleep until the eventfd internal
counter becomes greater than zero.
COPYRIGHTKernel Hackers Manual 3.11 November 2013 EVENTFD_CTX_READ(9)