Index: gbser_posix.cc
--- gbser_posix.cc.orig
+++ gbser_posix.cc
@@ -142,7 +142,7 @@ void* gbser_init(const char* port_name)
   if (0 == strcmp(port_name, "-")) {
     h->fd = 0;
     return h;
-  } else if (h->fd = open(port_name, O_RDWR | O_NOCTTY), h->fd == -1) {
+  } else if (h->fd = open(port_name, O_RDWR | O_NOCTTY | O_NDELAY), h->fd == -1) {
     gbWarning("Failed to open port (%s)\n", strerror(errno));
     goto failed;
   }
