diff --git a/libguac/include/guacio.h b/libguac/include/guacio.h
index 49055ba7..6b5ac161 100644
--- a/libguac/include/guacio.h
+++ b/libguac/include/guacio.h
@@ -216,6 +216,12 @@ ssize_t guac_flush(GUACIO* io);
  * Waits for input to be available on the given GUACIO object until the
  * specified timeout elapses.
  *
+ * If an error occurs while waiting, a negative value is returned, and
+ * guac_error is set appropriately.
+ *
+ * If a timeout occurs while waiting, zero value is returned, and
+ * guac_error is set to GUAC_STATUS_INPUT_TIMEOUT.
+ *
  * @param io The GUACIO object to wait for.
  * @param usec_timeout The maximum number of microseconds to wait for data, or
  *                     -1 to potentially wait forever.
diff --git a/libguac/src/guacio.c b/libguac/src/guacio.c
index da0b9e00..9ed2ba33 100644
--- a/libguac/src/guacio.c
+++ b/libguac/src/guacio.c
@@ -299,17 +299,28 @@ int guac_select(GUACIO* io, int usec_timeout) {
 
     fd_set fds;
     struct timeval timeout;
+    int retval;
 
+    /* No timeout if usec_timeout is negative */
     if (usec_timeout < 0)
-        return select(io->fd + 1, &fds, NULL, NULL, NULL); 
+        retval = select(io->fd + 1, &fds, NULL, NULL, NULL); 
 
-    timeout.tv_sec = usec_timeout/1000000;
-    timeout.tv_usec = usec_timeout%1000000;
+    /* Handle timeout if specified */
+    else {
+        timeout.tv_sec = usec_timeout/1000000;
+        timeout.tv_usec = usec_timeout%1000000;
 
-    FD_ZERO(&fds);
-    FD_SET(io->fd, &fds);
+        FD_ZERO(&fds);
+        FD_SET(io->fd, &fds);
 
-    return select(io->fd + 1, &fds, NULL, NULL, &timeout); 
+        retval = select(io->fd + 1, &fds, NULL, NULL, &timeout);
+    }
+
+    /* Properly set guac_error */
+    if (retval <  0) guac_error = GUAC_STATUS_INPUT_ERROR;
+    if (retval == 0) guac_error = GUAC_STATUS_INPUT_TIMEOUT;
+
+    return retval;
 
 }