《log4cplus日志库》
1. Preface
log4cplus是一款开源的c++日志库，具有线程安全，灵活，以及多粒度控制的特点；log4cplus可以将日志按照优先级进行划分，使其可以面向程序的调试，运行，测试，后期维护等软件全生命周期；可以通过配置，选择将日志输出到屏幕，文件，NT event log ,甚至是远程服务器。可通过配置控制日志的输出格式，也可通过指定策略对日志进行定期备份。
2. 源码下载编译
2.1 源码下载
log4cplus源码的下载可访问：log4cplus源码下载
2.2 编译
由于只在Linux和Windows两个平台使用c++，对cmake文件做一些改动；
log4clpus的主要源码位于目录src，以及include中，docs目录中为相关说明文档；
log4cplus根目录下CMakeLists.txt文件内容：
project (log4cplus)
cmake_minimum_required (VERSION 3.10)
# 编译器使用-fPIC选项，生成位置无关的代码
# 如果代码需要生成动态库供别人使用，建议增加此选项
# Use "-fPIC" / "-fPIE" for all targets by default, including static libs.
# https://blog.csdn.net/zhizhengguan/article/details/115323750
set (CMAKE_POSITION_INDEPENDENT_CODE ON)
# 针对MSVC编译器 进行设置 目标平台
if (MSVC)
#set (CMAKE_CXX_STANDARD 14) ARM平台
if (CMAKE_VS_PLATFORM_NAME MATCHES "ARM")
set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /EHsc")
endif ()
endif ()
# set_target_properties
# https://blog.csdn.net/weixin_39766005/article/details/122481172
# set (CXX_EXTENSIONS ON) # 全局设置
#set_target_properties(target PROPERTIES
# CXX_STANDARD 11
# CXX_STANDARD_REQUIRED ON
# CXX_EXTENSIONS ON
#)
# GUN安装目录
if(UNIX)
include(GNUInstallDirs)
endif(UNIX)
# include 包含文件 log4cplus_get_version()是定义的一个宏(类似函数)的东西
include (Log4CPlusUtils.cmake)
log4cplus_get_version ("${PROJECT_SOURCE_DIR}/include"
log4cplus_version_major log4cplus_version_minor log4cplus_version_patch)
message("-- Generating build for Log4cplus version ${log4cplus_version_major}.${log4cplus_version_minor}.${log4cplus_version_patch}")
set (log4cplus_soversion 3)
set (log4cplus_postfix "")
# option选项
option(LOG4CPLUS_BUILD_TESTING "Build the test suite." OFF)
option(LOG4CPLUS_BUILD_LOGGINGSERVER "Build the logging server." ON)
# 具体看代码中宏LOG4CPLUS_REQUIRE_EXPLICIT_INITIALIZATION定义
option(LOG4CPLUS_REQUIRE_EXPLICIT_INITIALIZATION "Require explicit initialization (see log4cplus::Initializer)" OFF)
if (LOG4CPLUS_REQUIRE_EXPLICIT_INITIALIZATION)
add_compile_definitions (LOG4CPLUS_REQUIRE_EXPLICIT_INITIALIZATION=1)
endif(LOG4CPLUS_REQUIRE_EXPLICIT_INITIALIZATION)
# add_compile_definitions: 添加宏定义 线程池使能
option(LOG4CPLUS_ENABLE_THREAD_POOL "Instantiate internal thread pool for when AsyncAppend=true" ON)
if (LOG4CPLUS_ENABLE_THREAD_POOL)
add_compile_definitions (LOG4CPLUS_ENABLE_THREAD_POOL=1)
endif()
# single thread 单线程开启
if(NOT LOG4CPLUS_SINGLE_THREADED)
find_package (Threads)
message (STATUS "Threads: ${CMAKE_THREAD_LIBS_INIT}")
endif(NOT LOG4CPLUS_SINGLE_THREADED)
if(LOG4CPLUS_SINGLE_THREADED AND LOG4CPLUS_BUILD_LOGGINGSERVER)
message (FATAL_ERROR "The logging server requires the multi-thread capability.")
endif(LOG4CPLUS_SINGLE_THREADED AND LOG4CPLUS_BUILD_LOGGINGSERVER)
set(BUILD_SHARED_LIBS TRUE CACHE BOOL "If TRUE, log4cplus is built as a shared library, otherwise as a static library")
if (WIN32)
set (UNICODE_DEFAULT OFF) # 修改位OFF
else (WIN32)
set (UNICODE_DEFAULT OFF)
endif (WIN32)
if (MSVC)
set (LOG4CPLUS_WORKING_LOCALE_DEFAULT ON)
else (MSVC)
set (LOG4CPLUS_WORKING_LOCALE_DEFAULT OFF)
endif (MSVC)
option(LOG4CPLUS_WORKING_LOCALE "Define for compilers/standard libraries that support more than just the C locale."
${LOG4CPLUS_WORKING_LOCALE_DEFAULT})
option(LOG4CPLUS_WORKING_C_LOCALE
"Define for compilers/standard libraries that have working C locale."
OFF)
option(LOG4CPLUS_SINGLE_THREADED
"Define if you want to build single-threaded version of the library."
OFF)
if (LOG4CPLUS_SINGLE_THREADED)
add_compile_definitions (LOG4CPLUS_SINGLE_THREADED=1)
endif (LOG4CPLUS_SINGLE_THREADED)
option(UNICODE "Build with tchar = wchar_t" ${UNICODE_DEFAULT})
option(WITH_ICONV "Use iconv() for char->wchar_t conversion."
OFF)
option(ENABLE_SYMBOLS_VISIBILITY
"Enable compiler and platform specific options for symbols visibility"
ON)
if (MINGW)
option(LOG4CPLUS_MINGW_STATIC_RUNTIME "Enable MinGW static runtime" OFF)
endif()
# WITH_UNIT_TESTS 修改位OFF
option(WITH_UNIT_TESTS "Enable unit tests" OFF)
if (WITH_UNIT_TESTS)
set (LOG4CPLUS_WITH_UNIT_TESTS 1)
add_compile_definitions (CATCH_CONFIG_PREFIX_ALL=1)
if (WIN32)
add_compile_definitions (LOG4CPLUS_WITH_UNIT_TESTS=1)
endif (WIN32)
endif (WITH_UNIT_TESTS)
# set(_WIN32_WINNT 0x0600 CACHE STRING "Define Windows API version to use.")
option(LOG4CPLUS_ENABLE_DECORATED_LIBRARY_NAME
"Turns on resulting file name decoration for static and UNICODE builds." OFF)
if (LOG4CPLUS_ENABLE_DECORATED_LIBRARY_NAME)
if (NOT ${BUILD_SHARED_LIBS})
# set S-prefix for static build
set (log4cplus_postfix "${log4cplus_postfix}S")
endif ()
if (UNICODE)
set (log4cplus_postfix "${log4cplus_postfix}U")
endif (UNICODE)
endif (LOG4CPLUS_ENABLE_DECORATED_LIBRARY_NAME)
set (log4cplus "log4cplus${log4cplus_postfix}")
if (WITH_ICONV)
set(LOG4CPLUS_WITH_ICONV 1)
endif ()
# 执行检查脚本 先检查是否有自定义脚本，如果没有，则将其设置位log4cplus提供的ConfigureChecks.cmake脚本，然后include
if(LOG4CPLUS_CONFIGURE_CHECKS_PATH)
get_filename_component(LOG4CPLUS_CONFIGURE_CHECKS_PATH "${LOG4CPLUS_CONFIGURE_CHECKS_PATH}" ABSOLUTE)
endif()
if(LOG4CPLUS_CONFIGURE_CHECKS_PATH AND EXISTS ${LOG4CPLUS_CONFIGURE_CHECKS_PATH})
message(STATUS "Custom ConfigureChecks script found: ${LOG4CPLUS_CONFIGURE_CHECKS_PATH}")
else()
set(LOG4CPLUS_CONFIGURE_CHECKS_PATH "ConfigureChecks.cmake")
endif()
# include 检查脚本，include具体做了什么？
include(${LOG4CPLUS_CONFIGURE_CHECKS_PATH})
# Prepare defines.hxx.cmake from defines.hxx.in by doing a bit of
# string manipulation.
file(READ include/log4cplus/config/defines.hxx.in FILE_BUFFER)
string(REGEX REPLACE "#undef[^a-zA-Z0-9_]+([a-zA-Z0-9_]+)"
"#cmakedefine \\1 @\\1@" FILE_BUFFER "${FILE_BUFFER}")
set(DEFINES_HXX_CMAKE
${log4cplus_BINARY_DIR}/include/log4cplus/config/defines.hxx.cmake)
set(DEFINES_HXX ${log4cplus_BINARY_DIR}/include/log4cplus/config/defines.hxx)
file(WRITE ${DEFINES_HXX_CMAKE} ${FILE_BUFFER})
configure_file(${DEFINES_HXX_CMAKE} ${DEFINES_HXX} @ONLY)
# 包含头文件
include_directories (${log4cplus_SOURCE_DIR}/include
${log4cplus_SOURCE_DIR}/threadpool
${log4cplus_SOURCE_DIR}/catch/single_include/catch2
${log4cplus_BINARY_DIR}/include
)
# 已经全局设置
# set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${PROJECT_BINARY_DIR}/bin)
if (LOG4CPLUS_BUILD_TESTING)
enable_testing()
endif (LOG4CPLUS_BUILD_TESTING)
# 构建
add_subdirectory (src)
# If the CMake version supports it, attach header directory information
# to the targets for when we are part of a parent build (ie being pulled
# in via add_subdirectory() rather than being a standalone build).
if (DEFINED CMAKE_VERSION AND NOT "${CMAKE_VERSION}" VERSION_LESS "2.8.11")
target_include_directories(${log4cplus} INTERFACE
$<BUILD_INTERFACE:${log4cplus_SOURCE_DIR}/include>
$<BUILD_INTERFACE:${log4cplus_BINARY_DIR}/include>)
endif()
if (LOG4CPLUS_BUILD_LOGGINGSERVER)
add_subdirectory (simpleserver)
endif (LOG4CPLUS_BUILD_LOGGINGSERVER)
if (LOG4CPLUS_BUILD_TESTING)
add_subdirectory (tests)
endif (LOG4CPLUS_BUILD_TESTING)
#include(Log4CPlusCPack.cmake)
message (STATUS "Compiler: ${CMAKE_CXX_COMPILER}")
message (STATUS "${CMAKE_CXX_COMPILER_ID} version ${CMAKE_CXX_COMPILER_VERSION}")
message (STATUS "Compiler flags: ${CMAKE_CXX_FLAGS}")
message (STATUS "System name: ${CMAKE_SYSTEM_NAME}")
message (STATUS "System version: ${CMAKE_SYSTEM_VERSION}")