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EVENTFD_CTX_READ(9) Events based on file descripto EVENTFD_CTX_READ(9)

NAME

eventfd_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

struct eventfd_ctx * ctx
[in] Pointer to eventfd context.

int no_wait

[in] Different from zero if the operation should not block.

__u64 * 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.

COPYRIGHT

September 2017 Kernel Hackers Manual 4.12