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-rw-r--r--src/zmq.cpp54
1 files changed, 37 insertions, 17 deletions
diff --git a/src/zmq.cpp b/src/zmq.cpp
index 1ed96df..c40be65 100644
--- a/src/zmq.cpp
+++ b/src/zmq.cpp
@@ -452,31 +452,25 @@ int zmq_poll (zmq_pollitem_t *items_, int nitems_, long timeout_)
maxfd = notify_fd;
}
+ bool block = (timeout_ < 0);
timeval timeout = {timeout_ / 1000000, timeout_ % 1000000};
timeval zero_timeout = {0, 0};
int nevents = 0;
- bool initial = true;
- while (!nevents) {
- // Wait for activity. In the first iteration just check for events,
- // don't wait. Waiting would prevent exiting on any events that may
- // already be signaled on 0MQ sockets.
- int rc = select (maxfd, &pollset_in, &pollset_out, &pollset_err,
- initial ? &zero_timeout : &timeout);
+ // First iteration just check for events, don't block. Waiting would
+ // prevent exiting on any events that may already been signaled on
+ // 0MQ sockets.
+ int rc = select (maxfd, &pollset_in, &pollset_out, &pollset_err,
+ &zero_timeout);
#if defined ZMQ_HAVE_WINDOWS
- wsa_assert (rc != SOCKET_ERROR);
+ wsa_assert (rc != SOCKET_ERROR);
#else
- if (rc == -1 && errno == EINTR)
- break;
+ if (rc == -1 && errno == EINTR)
+ break;
+ errno_assert (rc >= 0);
#endif
- errno_assert (rc >= 0);
- // If timeout was hit with no events signaled, return zero.
- if (!initial && rc == 0)
- return 0;
-
- // From now on, perform blocking select.
- initial = false;
+ while (true) {
// Process 0MQ commands if needed.
if (nsockets && FD_ISSET (notify_fd, &pollset_in))
@@ -507,6 +501,32 @@ int zmq_poll (zmq_pollitem_t *items_, int nitems_, long timeout_)
if (items_ [i].revents)
nevents++;
}
+
+ // If there's at least one event, or if we are asked not to block,
+ // return immediately.
+ if (nevents || (timeout.tv_sec == 0 && timeout.tv_usec == 0))
+ break;
+
+ // Wait for events.
+ int rc = select (maxfd, &pollset_in, &pollset_out, &pollset_err,
+ block ? NULL : &timeout);
+#if defined ZMQ_HAVE_WINDOWS
+ wsa_assert (rc != SOCKET_ERROR);
+#else
+ if (rc == -1 && errno == EINTR)
+ break;
+ errno_assert (rc >= 0);
+#endif
+
+ // If timeout was hit with no events signaled, return zero.
+ if (rc == 0)
+ break;
+
+ // If timeout was already applied, we don't want to poll anymore.
+ // Setting timeout to zero will cause termination of the function
+ // once the events we've got are processed.
+ if (!block)
+ timeout = zero_timeout;
}
return nevents;