CMake教程

构建可执行程序

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add_executable(demo demo.cxx)

添加版本号

cmakelists.txt写入：

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cmake_minimum_required(VERSION 2.6)
project(Demo)
# 版本号 1.0
set(Demo_VERSION_MAJOR 1)
set(Demo_VERSION_MINOR 0)

# 用.in文件生成.h文件
configure_file(
        "${PROJECT_SOURCE_DIR}/DemoConfig.h.in"
        "${PROJECT_BINARY_DIR}/DemoConfig.h"
)

include_directories("${PROJECT_BINARY_DIR}")

add_executable(demo demo.cpp)

新建DemoConfig.h.in文件，写入：

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#define VERSION_MAJOR @Demo_VERSION_MAJOR@
#define VERSION_MINOR @Demo_VERSION_MINOR@

新建demo.cpp文件，写入：

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#include <stdio.h>
#include "DemoConfig.h"

int main (int argc, char *argv[])
{
    fprintf(stdout, "%s --- 版本号： %d.%d\n",
            argv[0],
            VERSION_MAJOR,
            VERSION_MINOR);
    return 0;
}

打印版本号。

为什么不直接把版本号写到源码里呢？当然可以，写在cmake配置文件里比较灵活。

添加一个库

新建一个目录，名为MathFunctions,里面新建两个文件，MathFunctions.h和math.cpp。
.h文件里写入：

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#ifndef DEMO_MATHFUNCTIONS_H
#define DEMO_MATHFUNCTIONS_H
int square(int x);
#endif //DEMO_MATHFUNCTIONS_H

.cpp文件里写入:

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int square(int x) {
    int res;
    res = x * x;
    return res;
}

然后在此目录中新建一个``CmakeLists.txt`，写入：

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add_library(MathFunctions math.cpp)

回到父目录，DemoConfig.h.in里写入:

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#cmakedefine USE_MYMATH

回到父目录的cmkaelist.txt文件中，修改为:

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cmake_minimum_required(VERSION 2.6)
project(Demo)
# 版本号 1.0
set(Demo_VERSION_MAJOR 1)
set(Demo_VERSION_MINOR 0)

# 用.in文件生成.h文件
configure_file(
        "${PROJECT_SOURCE_DIR}/DemoConfig.h.in"
        "${PROJECT_BINARY_DIR}/DemoConfig.h"
)

include_directories("${PROJECT_BINARY_DIR}")

# 是否使用我们自己的函数？
option(USE_MYMATH
        "Use demo provided math implementation" ON)

# add the MathFunctions library?
if (USE_MYMATH)
    include_directories("${PROJECT_SOURCE_DIR}/MathFunctions")
    add_subdirectory(MathFunctions)
    set(EXTRA_LIBS ${EXTRA_LIBS} MathFunctions)
endif (USE_MYMATH)

# add the executable
add_executable(demo demo.cpp)
target_link_libraries(demo ${EXTRA_LIBS})

在demo.cpp里测试一下:

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#include <stdio.h>
#include "DemoConfig.h"
#ifdef USE_MYMATH
#include "MathFunctions.h"
#endif

int main (int argc, char *argv[])
{
    fprintf(stdout, "%s --- 版本号： %d.%d\n",
            argv[0],
            VERSION_MAJOR,
            VERSION_MINOR);

    printf("%d\n",square(5));
    return 0;
}

安装与打包

先安装NSIS程序：https://nsis.sourceforge.io/Main_Page

顶层cmakelists.txt中写入：

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# add the install targets
install (TARGETS demo DESTINATION bin)
install (FILES "${PROJECT_BINARY_DIR}/DemoConfig.h"
        DESTINATION include)

# build a CPack driven installer package
include (InstallRequiredSystemLibraries)
set (CPACK_RESOURCE_FILE_LICENSE
        "${CMAKE_CURRENT_SOURCE_DIR}/License.txt")
set (CPACK_PACKAGE_VERSION_MAJOR "${demo_VERSION_MAJOR}")
set (CPACK_PACKAGE_VERSION_MINOR "${demo_VERSION_MINOR}")
include (CPack)

mathfunctions目录中的cmakelists.txt中写入：

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install (TARGETS MathFunctions DESTINATION bin)
install (FILES MathFunctions.h DESTINATION include)

命令行运行：

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cpack --config CPackConfig.cmake

生成了Demo–win64.exe安装程序。