From 2bc1140f597f9d6678de6146ca8fa87f79bd20bd Mon Sep 17 00:00:00 2001
From: Phil Carns <carns@mcs.anl.gov>
Date: Sat, 20 May 2017 18:39:42 +0200
Subject: [PATCH] make register_mplex allow 0 mplex id

---
 include/margo.h | 1 +
 src/margo.c     | 6 +++---
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/margo.h b/include/margo.h
index 39fa802..f3666a2 100644
--- a/include/margo.h
+++ b/include/margo.h
@@ -20,6 +20,7 @@ struct margo_instance;
 typedef struct margo_instance* margo_instance_id;
 
 #define MARGO_INSTANCE_NULL ((margo_instance_id)NULL)
+#define MARGO_DEFAULT_MPLEX_ID 0
 
 
 /**
diff --git a/src/margo.c b/src/margo.c
index e36a2bf..86f4fa2 100644
--- a/src/margo.c
+++ b/src/margo.c
@@ -833,9 +833,9 @@ int margo_register_mplex(margo_instance_id mid, hg_id_t id, uint32_t mplex_id, A
     struct mplex_key key;
     struct mplex_element *element;
 
-    /* mplex_id can't be zero; that's the default handler pool */
-    if(!mplex_id)
-        return(-1);
+    /* nothing to do, we'll let the handler pool take this directly */
+    if(mplex_id == MARGO_DEFAULT_MPLEX_ID)
+        return(0);
 
     memset(&key, 0, sizeof(key));
     key.id = id;
-- 
2.26.2