Add mult exec example (cpp-redis#31)

Author: theidexisted

examples/CMakeLists.txt

@@ -47,6 +47,7 @@ set(EXAMPLES cpp_redis_client
               cpp_redis_kill
               cpp_redis_streams_client
               cpp_redis_high_availability_client
+              cpp_redis_multi_exec
     )
 
 foreach(EXAMPLE IN ITEMS ${EXAMPLES})

examples/cpp_redis_multi_exec.cpp

@@ -0,0 +1,35 @@
+// The MIT License (MIT)
+
+#include "winsock_initializer.h"
+#include <cpp_redis/cpp_redis>
+#include <string>
+
+int
+main(void) {
+  winsock_initializer winsock_init;
+  cpp_redis::client client;
+
+  client.connect("127.0.0.1", 6379,
+    [](const std::string& host, std::size_t port, cpp_redis::connect_state status) {
+      if (status == cpp_redis::connect_state::dropped) {
+        std::cout << "client disconnected from " << host << ":" << port << std::endl;
+      }
+    });
+  client.multi([](cpp_redis::reply& reply) {
+    std::cout << "transaction start:" << reply << std::endl;
+  });
+  client.set("hello", "42", [](cpp_redis::reply& reply) {
+    std::cout << "set hello 42: " << reply << std::endl;
+  });
+  client.decrby("hello", 12, [](cpp_redis::reply& reply) {
+    std::cout << "decrby hello 12: " << reply << std::endl;
+  });
+  // Previous two commands will be queued until exec called
+  client.exec([](cpp_redis::reply& reply) {
+    std::cout << "transaction end:" << reply << std::endl;
+  });
+
+  client.sync_commit();
+
+  return 0;
+}