Modified message.cpp to use the new feature.

CMakeLists.txt

@@ -16,6 +16,8 @@ set(CPPKAFKA_VERSION "${CPPKAFKA_VERSION_MAJOR}.${CPPKAFKA_VERSION_MINOR}.${CPPK
 set(RDKAFKA_MIN_VERSION "0.9.4")
 set(RDKAFKA_MIN_VERSION_HEX 0x00090400)
 
+option(USE_CPP17 "Use C++17 features instead of Boost (still, if you don't have boost you can't build examples" OFF)
+
 if (NOT CMAKE_CXX_FLAGS)
     # Set default compile flags for the project
     if(MSVC)
@@ -31,8 +33,13 @@ if (NOT CMAKE_CXX_FLAGS)
         set(CMAKE_CXX_FLAGS "-Wall")
     endif()
 endif()
-# Use C++17
-set(CMAKE_CXX_STANDARD 17)
+
+if(USE_CPP17)
+    set(CMAKE_CXX_STANDARD 17)
+    add_definitions("-D_USE_CPP17")
+else()
+    set(CMAKE_CXX_STANDARD 11)
+endif()
 
 # Set output directories
 set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/lib)
@@ -104,32 +111,11 @@ if (NOT CPPKAFKA_PKGCONFIG_DIR)
     set(CPPKAFKA_PKGCONFIG_DIR share/pkgconfig)
 endif()
 
-# Try to find the RdKafka configuration file if present.
-# This will search default system locations as well as RdKafka_ROOT and RdKafka_Dir paths if specified.
-find_package(RdKafka ${FIND_PACKAGE_QUIET} CONFIG)
-set(RDKAFKA_TARGET_IMPORTS ${RdKafka_FOUND})
-if (NOT RdKafka_FOUND)
-    message(STATUS "RdKafkaConfig.cmake not found. Attempting to find module instead...")
-    find_package(RdKafka REQUIRED ${FIND_PACKAGE_QUIET} MODULE)
-    if (NOT RdKafka_FOUND)
-        message(FATAL_ERROR "RdKafka module not found. Please set RDKAFKA_ROOT to the install path or RDKAFKA_DIR pointing to the RdKafka configuration file location.")
-    else()
-        message(STATUS "RdKafka module found.")
-    endif()
-else()
-    message(STATUS "RdKafka configuration file found: ${RdKafka_CONFIG}")
-endif()
-
-add_subdirectory(src)
-add_subdirectory(include/cppkafka)
-
-# Examples target
-if (NOT CPPKAFKA_DISABLE_EXAMPLES)
+if(NOT USE_CPP17 OR NOT CPPKAFKA_DISABLE_EXAMPLES OR NOT CPPKAFKA_DISABLE_TESTS)
     # Look for Boost (just need boost.optional headers here)
-    find_package(Boost ${FIND_PACKAGE_QUIET} CONFIG)
+    find_package(Boost REQUIRED ${FIND_PACKAGE_QUIET})
+
     if (Boost_FOUND)
-        option(CPPKAFKA_BOOST_STATIC_LIBS "Link with Boost static libraries." ON)
-        option(CPPKAFKA_BOOST_USE_MULTITHREADED "Use Boost multithreaded libraries." ON)
         find_package(Boost COMPONENTS program_options ${FIND_PACKAGE_QUIET})
         set(Boost_USE_STATIC_LIBS ${CPPKAFKA_BOOST_STATIC_LIBS})
         set(Boost_USE_MULTITHREADED ${CPPKAFKA_BOOST_USE_MULTITHREADED})
@@ -142,12 +128,37 @@ if (NOT CPPKAFKA_DISABLE_EXAMPLES)
             message(STATUS "Boost is multi-threaded: ${CPPKAFKA_BOOST_USE_MULTITHREADED}")
             message(STATUS "Boost libraries: ${Boost_LIBRARIES}")
         endif()
+    endif()
+
+    # Examples target
+    if (Boost_PROGRAM_OPTIONS_FOUND)
         add_subdirectory(examples)
     else()
         message(STATUS "Disabling examples")
     endif()
 endif()
 
+# Try to find the RdKafka configuration file if present.
+# This will search default system locations as well as RdKafka_ROOT and RdKafka_Dir paths if specified.
+find_package(RdKafka ${FIND_PACKAGE_QUIET} CONFIG)
+set(RDKAFKA_TARGET_IMPORTS ${RdKafka_FOUND})
+if (NOT RdKafka_FOUND)
+    message(STATUS "RdKafkaConfig.cmake not found. Attempting to find module instead...")
+    find_package(RdKafka REQUIRED ${FIND_PACKAGE_QUIET} MODULE)
+    if (NOT RdKafka_FOUND)
+        message(FATAL_ERROR "RdKafka module not found. Please set RDKAFKA_ROOT to the install path or RDKAFKA_DIR pointing to the RdKafka configuration file location.")
+    else()
+        message(STATUS "RdKafka module found.")
+    endif()
+else()
+    message(STATUS "RdKafka configuration file found: ${RdKafka_CONFIG}")
+endif()
+
+add_subdirectory(src)
+add_subdirectory(include/cppkafka)
+
+
+
 # Add a target to generate API documentation using Doxygen
 find_package(Doxygen ${FIND_PACKAGE_QUIET})
 if(DOXYGEN_FOUND)
@@ -188,4 +199,4 @@ if(NOT TARGET uninstall)
     # Add uninstall target
     add_custom_target(uninstall
         COMMAND ${CMAKE_COMMAND} -P ${CMAKE_CURRENT_BINARY_DIR}/cmake_uninstall.cmake)
-endif()
+endif()

include/cppkafka/cppkafka.h

@@ -57,11 +57,13 @@
 #include <cppkafka/topic_configuration.h>
 #include <cppkafka/topic_partition.h>
 #include <cppkafka/topic_partition_list.h>
+#include <cppkafka/utils/any.h>
 #include <cppkafka/utils/backoff_committer.h>
 #include <cppkafka/utils/backoff_performer.h>
 #include <cppkafka/utils/buffered_producer.h>
 #include <cppkafka/utils/compacted_topic_processor.h>
 #include <cppkafka/utils/consumer_dispatcher.h>
+#include <cppkafka/utils/optional.h>
 #include <cppkafka/utils/poll_interface.h>
 #include <cppkafka/utils/poll_strategy_base.h>
 #include <cppkafka/utils/roundrobin_poll_strategy.h>

include/cppkafka/message.h

@@ -34,7 +34,7 @@
 #include <cstdint>
 #include <chrono>
 #include <cassert>
-#include <optional>
+#include "utils/optional.h"
 #include <librdkafka/rdkafka.h>
 #include "buffer.h"
 #include "macros.h"
@@ -189,7 +189,7 @@ class CPPKAFKA_API Message {
      *
      * If calling rd_kafka_message_timestamp returns -1, then boost::none_t will be returned.
      */
-    std::optional<MessageTimestamp> get_timestamp() const;
+    optional<MessageTimestamp> get_timestamp() const;
 
 #if RD_KAFKA_VERSION >= RD_KAFKA_MESSAGE_LATENCY_SUPPORT_VERSION
     /**

src/CMakeLists.txt

@@ -49,7 +49,7 @@ set_target_properties(${TARGET_NAME} PROPERTIES
 # In CMake >= 3.15 Boost::boost == Boost::headers
 target_link_libraries(${TARGET_NAME} PUBLIC RdKafka::rdkafka)
 
-if(NOT CPPKAFKA_DISABLE_EXAMPLES)
+if(NOT USE_CPP17 OR NOT CPPKAFKA_DISABLE_EXAMPLES OR NOT CPPKAFKA_DISABLE_TESTS)
     target_link_libraries(${TARGET_NAME} PUBLIC Boost::boost)
 endif()
 

src/message.cpp

@@ -84,7 +84,7 @@ Message& Message::load_internal() {
     return *this;
 }
 
-std::optional<MessageTimestamp> Message::get_timestamp() const {
+optional<MessageTimestamp> Message::get_timestamp() const {
     rd_kafka_timestamp_type_t type = RD_KAFKA_TIMESTAMP_NOT_AVAILABLE;
     int64_t timestamp = rd_kafka_message_timestamp(handle_.get(), &type);
     if (timestamp == -1 || type == RD_KAFKA_TIMESTAMP_NOT_AVAILABLE) {