ZMQII-55: At most one PGM/UDP transport can be opened

src/pgm_socket.cpp

@@ -78,17 +78,18 @@ int zmq::pgm_socket_t::init (bool udp_encapsulation_, const char *network_)
     nbytes_processed = 0;
     pgm_msgv_processed = 0;
 
+    int rc;
     GError *pgm_error = NULL;
 
-    //  Init PGM transport.
+    //  Init PGM transport if not already done.
     //  Ensure threading enabled, ensure timer enabled and find PGM protocol id.
     //
     //  Note that if you want to use gettimeofday and sleep for openPGM timing,
     //  set environment variables PGM_TIMER to "GTOD" 
     //  and PGM_SLEEP to "USLEEP".
-    int rc = pgm_init (&pgm_error);
+    if (!pgm_supported ()) {
+        rc = pgm_init (&pgm_error);
         if (rc != TRUE) {
-
             if (pgm_error->domain == PGM_IF_ERROR && (
                   pgm_error->code == PGM_IF_ERROR_INVAL ||
                   pgm_error->code == PGM_IF_ERROR_XDEV ||
@@ -106,6 +107,7 @@ int zmq::pgm_socket_t::init (bool udp_encapsulation_, const char *network_)
 
             zmq_assert (false);
         }
+    }
 
     //  PGM transport GSI.
     pgm_gsi_t gsi;