Expired survey returns ETIMEDOUT instead of EAGAIN

Up to now, when survey in surveyor pattern expired, xs_recv()
returned EAGAIN. That made it impossible to distinguish
epired survey from expired receive timeout (XS_RCVTIMEO).
This patch make errors different in both cases.

Signed-off-by: Martin Sustrik <sustrik@250bpm.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/src/surveyor.cpp b/src/surveyor.cpp
index b72b91b..bd19b8a 100644
--- a/src/surveyor.cpp
+++ b/src/surveyor.cpp
@@ -92,8 +92,16 @@ int xs::surveyor_t::xrecv (msg_t *msg_, int flags_)
 
     //  Get the first part of the response -- the survey ID.
     rc = xsurveyor_t::xrecv (msg_, flags_);
-    if (rc != 0)
-        return rc;
+    if (rc != 0) {
+        if (errno != EAGAIN)
+            return -1;
+
+        //  In case of AGAIN we should check whether the survey timeout expired.
+        //  If so, we should return ETIMEDOUT so that user is able to
+        //  distinguish survey timeout from RCVTIMEO-caused timeout.
+        errno = now_ms () >= timeout ? ETIMEDOUT : EAGAIN;
+        return -1;
+    }
 
     //  Check whether this is response for the onging survey. If not, we can
     //  drop the response.