From 16f16eeaad53daefee243d96b7ecdff60ac92eac Mon Sep 17 00:00:00 2001
From: Gudmundur Adalsteinsson <ofpgummi@yahoo.com>
Date: Thu, 4 Apr 2019 17:55:27 +0000
Subject: [PATCH] Problem: message_t lacks empty() function

Solution: Add function and qualify with nodiscard like std types
---
 tests/message.cpp | 3 +++
 zmq.hpp           | 5 +++++
 2 files changed, 8 insertions(+)

diff --git a/tests/message.cpp b/tests/message.cpp
index 005d6c8..15f0484 100644
--- a/tests/message.cpp
+++ b/tests/message.cpp
@@ -17,6 +17,7 @@ TEST_CASE("message default constructed", "[message]")
 {
     const zmq::message_t message;
     CHECK(0u == message.size());
+    CHECK(message.empty());
 }
 
 #ifdef ZMQ_CPP11
@@ -89,8 +90,10 @@ TEST_CASE("message assign move empty before", "[message]")
 TEST_CASE("message assign move empty after", "[message]")
 {
     zmq::message_t hi_msg(data, strlen(data));
+    CHECK(!hi_msg.empty());
     hi_msg = zmq::message_t();
     CHECK(0u == hi_msg.size());
+    CHECK(hi_msg.empty());
 }
 
 TEST_CASE("message assign move empty before and after", "[message]")
diff --git a/zmq.hpp b/zmq.hpp
index ad9e9db..f98549d 100644
--- a/zmq.hpp
+++ b/zmq.hpp
@@ -396,6 +396,11 @@ class message_t
         return zmq_msg_size(const_cast<zmq_msg_t *>(&msg));
     }
 
+    ZMQ_NODISCARD bool empty() const ZMQ_NOTHROW
+    {
+        return size() == 0u;
+    }
+
     template<typename T> T *data() ZMQ_NOTHROW { return static_cast<T *>(data()); }
 
     template<typename T> T const *data() const ZMQ_NOTHROW