Problem: zmq_poller_* uses ETIMEDOUT (instead of the usual EAGAIN) to…

… indicate timeouts

Solution: replace ETIMEDOUT within socket_poller_t and all client code by EAGAIN

Fixes #2713

src/proxy.cpp

@@ -271,13 +271,13 @@ int zmq::proxy (
  // If one of receiving end's queue is full ('ZMQ_POLLOUT' not available),
  // 'poller_wait' is pointed to 'poller_receive_blocked', 'poller_send_blocked' or 'poller_both_blocked'.
  rc = poller_wait->wait (events, 3, -1);
- if (rc < 0 && errno == ETIMEDOUT)
+ if (rc < 0 && errno == EAGAIN)
  rc = 0;
  CHECK_RC_EXIT_ON_FAILURE ();
 
  // Some of events waited for by 'poller_wait' have arrived, now poll for everything without blocking.
  rc = poller_all->wait (events, 3, 0);
- if (rc < 0 && errno == ETIMEDOUT)
+ if (rc < 0 && errno == EAGAIN)
  rc = 0;
  CHECK_RC_EXIT_ON_FAILURE ();
 

src/socket_poller.cpp

@@ -415,7 +415,7 @@ int zmq::socket_poller_t::wait (zmq::socket_poller_t::event_t *events_, int n_ev
  // no event occured within the specified timeout. Otherwise the caller
  // needs to check the return value AND the event to avoid using the
  // nullified event data.
- errno = ETIMEDOUT;
+ errno = EAGAIN;
  if (timeout_ == 0)
  return -1;
 #if defined ZMQ_HAVE_WINDOWS
@@ -550,7 +550,7 @@ int zmq::socket_poller_t::wait (zmq::socket_poller_t::event_t *events_, int n_ev
  if (now >= end)
  break;
  }
- errno = ETIMEDOUT;
+ errno = EAGAIN;
  return -1;
 
 #elif defined ZMQ_POLL_BASED_ON_SELECT
@@ -560,7 +560,7 @@ int zmq::socket_poller_t::wait (zmq::socket_poller_t::event_t *events_, int n_ev
  // no event occured within the specified timeout. Otherwise the caller
  // needs to check the return value AND the event to avoid using the
  // nullified event data.
- errno = ETIMEDOUT;
+ errno = EAGAIN;
  if (timeout_ == 0)
  return -1;
 #if defined ZMQ_HAVE_WINDOWS
@@ -711,7 +711,7 @@ int zmq::socket_poller_t::wait (zmq::socket_poller_t::event_t *events_, int n_ev
  break;
  }
 
- errno = ETIMEDOUT;
+ errno = EAGAIN;
  return -1;
 
 #else

src/zmq.cpp

@@ -813,7 +813,7 @@ inline int zmq_poller_poll (zmq_pollitem_t *items_, int nitems_, long timeout_)
  rc = zmq_poller_wait_all (&poller, events, nitems_, timeout_);
  if (rc < 0) {
  delete [] events;
- if (zmq_errno() == ETIMEDOUT) {
+ if (zmq_errno() == EAGAIN) {
  return 0;
  }
  return rc;

tests/test_poller.cpp

@@ -170,18 +170,16 @@ void test_wait_corner_cases (void *ctx)
  void *poller = zmq_poller_new ();
  assert (poller != NULL);
 
- // TODO zmq_poller_wait should return EAGAIN instead of ETIMEDOUT (like all other zmq functions)
-
  zmq_poller_event_t event;
  int rc = zmq_poller_wait(poller, &event, 0);
- assert (rc == -1 && errno == ETIMEDOUT);
+ assert (rc == -1 && errno == EAGAIN);
 
  // this can never return since no socket was registered, and should yield an error
  rc = zmq_poller_wait(poller, &event, -1);
  assert (rc == -1 && errno == EFAULT);
 
  rc = zmq_poller_wait_all (poller, &event, 0, 0);
- assert (rc == -1 && errno == ETIMEDOUT);
+ assert (rc == -1 && errno == EAGAIN);
 
  // this can never return since no socket was registered, and should yield an error
  rc = zmq_poller_wait_all (poller, &event, 0, -1);
@@ -238,7 +236,7 @@ int main (void)
  // waiting on poller with no registered sockets should report error
  rc = zmq_poller_wait (poller, &event, 0);
  assert (rc == -1);
- assert (errno == ETIMEDOUT);
+ assert (errno == EAGAIN);
 
  // register sink
  rc = zmq_poller_add (poller, sink, sink, ZMQ_POLLIN);
@@ -260,7 +258,7 @@ int main (void)
  // We expect timed out
  rc = zmq_poller_wait (poller, &event, 0);
  assert (rc == -1);
- assert (errno == ETIMEDOUT);
+ assert (errno == EAGAIN);
 
  // Stop polling sink
  rc = zmq_poller_remove (poller, sink);