Fix unused-variable warning in perf/proxy_thr.cpp

RELICENSE/lstacul.md

+# Permission to Relicense under MPLv2
+
+This is a statement by Laurent Stacul
+that grants permission to relicense its copyrights in the libzmq C++
+library (ZeroMQ) under the Mozilla Public License v2 (MPLv2).
+
+A portion of the commits made by the Github handle "stac47", with
+commit author "Laurent Stacul <laurent.stacul@gmail.com>", are copyright of
+Laurent Stacul .
+This document hereby grants the libzmq project team to relicense libzmq, 
+including all past, present and future contributions of the author listed above.
+
+Laurent Stacul
+2020/02/21

perf/proxy_thr.cpp

@@ -74,6 +74,14 @@
 #define TEST_ASSERT_SUCCESS_ERRNO(expr)                                        \
     test_assert_success_message_errno_helper (expr, NULL, #expr)
 
+// This macro is used to avoid-variable warning. If used with an expression,
+// the sizeof is not evaluated to avoid polluting the assembly code.
+#ifdef NDEBUG
+#define ASSERT_EXPR_SAFE(x) do { (void)sizeof(x);} while (0)
+#else
+#define ASSERT_EXPR_SAFE(x) assert(x)
+#endif
+
 
 static uint64_t message_count = 0;
 static size_t message_size = 0;
@@ -238,7 +246,7 @@ static void proxy_thread_main (void *pvoid)
         if (ep != NULL) {
             assert (strlen (ep) > 5);
             rc = zmq_bind (frontend_xsub, ep);
-            assert (rc == 0);
+            ASSERT_EXPR_SAFE (rc == 0);
         }
     }
 
@@ -252,7 +260,7 @@ static void proxy_thread_main (void *pvoid)
     int optval = 1;
     rc =
       zmq_setsockopt (backend_xpub, ZMQ_XPUB_NODROP, &optval, sizeof (optval));
-    assert (rc == 0);
+    ASSERT_EXPR_SAFE (rc == 0);
 
     set_hwm (backend_xpub);
 
@@ -262,7 +270,7 @@ static void proxy_thread_main (void *pvoid)
         if (ep != NULL) {
             assert (strlen (ep) > 5);
             rc = zmq_bind (backend_xpub, ep);
-            assert (rc == 0);
+            ASSERT_EXPR_SAFE (rc == 0);
         }
     }
 
@@ -275,7 +283,7 @@ static void proxy_thread_main (void *pvoid)
 
     //  Bind CONTROL
     rc = zmq_bind (control_rep, cfg->control_endpoint);
-    assert (rc == 0);
+    ASSERT_EXPR_SAFE (rc == 0);
 
     //  Start proxying!
 
@@ -298,12 +306,12 @@ void terminate_proxy (const proxy_hwm_cfg_t *cfg)
 
     //  Connect CONTROL-REQ: a socket to which send commands
     int rc = zmq_connect (control_req, cfg->control_endpoint);
-    assert (rc == 0);
+    ASSERT_EXPR_SAFE (rc == 0);
 
     //  Ask the proxy to exit: the subscriber has received all messages
 
     rc = zmq_send (control_req, "TERMINATE", 9, 0);
-    assert (rc == 9);
+    ASSERT_EXPR_SAFE (rc == 9);
 
     zmq_close (control_req);
 }
@@ -327,7 +335,7 @@ int main (int argc, char *argv[])
     assert (context);
 
     int rv = zmq_ctx_set (context, ZMQ_IO_THREADS, 4);
-    assert (rv == 0);
+    ASSERT_EXPR_SAFE (rv == 0);
 
     //  START ALL SECONDARY THREADS
 
@@ -395,7 +403,7 @@ int main (int argc, char *argv[])
     zmq_threadclose (proxy);
 
     int rc = zmq_ctx_term (context);
-    assert (rc == 0);
+    ASSERT_EXPR_SAFE (rc == 0);
 
     return 0;
 }