CMake 极简入门

本文根据《cmake实践.pdf》写的并简化一些内容

项目地址

---

p1 最简单的hello world

文件结构(其他均为cmake生成的文件)

CMakeLists.txt

main.c

main.c

#include <stdio.h>
int main(){
    printf("Hello World use Cmake :)\n");
    return 0;
}

CMakeLists.txt

#设置项目名称 HELLO
PROJECT (HELLO)

#变量SRC_LIST 赋值 main.c
SET(SRC_LIST main.c)

#MESSAGE 输出log 
#SEND_ERROR，产生错误，生成过程被跳过
#SATUS，输出前缀为—的信息
#FATAL_ERROR，立即终止所有 cmake 过程
#${}取出变量值
MESSAGE(STATUS "This is BINARY dir " ${HELLO_BINARY_DIR}) 

#隐式变量 HELLO_SOURCE_DIR 即  <项目名称>_SOURCE_DIR
MESSAGE(STATUS "This is SOURCE dir " ${HELLO_SOURCE_DIR}) 

#ADD_EXECUTABLE 生产执行文件
ADD_EXECUTABLE(hello ${SRC_LIST})

编译运行

cmake

make

./hello

p2 多个文件的hello world

CMakeLists.txt

main.c

fun.h

fun.c

---

fun.h

#include <stdio.h>
void fun();

fun.c

void fun(){
    printf("call fun \n");
}

main.c

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

int main(){
    fun();
    return 0;
}

CMakeLists.txt

PROJECT(P2_COMMAND)

#变量赋值
SET(PARAM 'this is param')

#赋多个值 给变量SRC
SET(SRC main.c fun.h fun.c)

MESSAGE(STATUS 'PARAM :' ${PARAM})
MESSAGE(STATUS 'SRC:' ${SRC})

#生成执行文件fun
ADD_EXECUTABLE(fun ${SRC})

编译运行

cmake

make

./hello

p3 结构化的hello world

CMakeLists.txt

src\main.c CMakeLists.txt

bin\

---

CMakeLists.txt

PROJECT(HELLO) 

#添加子目录 并在该目录下自动寻找CMakeLists.txt 运行
ADD_SUBDIRECTORY(src bin)

#EXECUTABLE_OUTPUT_PATH 常量变量 输出可执行路径
#PROJECT_BINARY_DIR 常量变量
SET(EXECUTABLE_OUTPUT_PATH ${PROJECT_BINARY_DIR}/bin)

#LIBRARY_OUTPUT_PATH 动态库输出路径
SET(LIBRARY_OUTPUT_PATH ${PROJECT_BINARY_DIR}/lib)

MESSAGE(STATUS EXECUTABLE_OUTPUT_PATH ${EXECUTABLE_OUTPUT_PATH})
MESSAGE(STATUS LIBRARY_OUTPUT_PATH ${LIBRARY_OUTPUT_PATH})

src\CMakeLists.txt

ADD_EXECUTABLE(hello main.c)

编译运行

cd build

cmake ..

make

./hello

p4 编译动态库 并且链接库

CMakeLists.txt

bin/

lib/CMakeLists.txt hello.c hello.h

---

lib/hello.h

#ifndef HELLO_H
#define HELLO_H

#include <stdio.h>
void sayHello();
#endif

lib/hello.c

#include "hello.h"

void sayHello(){
    printf("Hello World :) \n");
}

CMakeLists.txt

PROJECT(HELLOLIB)

ADD_SUBDIRECTORY(lib)

lib/CMakeLists.txt

SET(LIBHELLO_SRC hello.c)

ADD_LIBRARY(hello SHARED ${LIBHELLO_SRC})
#ADD_LIBRARY(hello STATIC ${LIBHELLO_SRC})
ADD_LIBRARY(hello_static STATIC ${LIBHELLO_SRC})

#静态库hello_static重命名输出hello
SET_TARGET_PROPERTIES(hello_static PROPERTIES OUTPUT_NAME "hello")

#OUTPUT_VALUE 赋值 hello_static. OUTPUT_NAME
GET_TARGET_PROPERTY(OUTPUT_VALUE hello_static OUTPUT_NAME)
MESSAGE(STATUS "This is the hello_static OUTPUT_NAME:"${OUTPUT_VALUE})

#设置版本信息
SET_TARGET_PROPERTIES(hello PROPERTIES VERSION 1.2 SOVERSION 1)

#安装指令
#INSTALL(TARGETS hello hello_static LIBRARY DESTINATION lib ARCHIVE DESTINATION lib)

编译运行

cd build
cmake ..
make

p5 链接外部库

CMakeLists.txt build/ src/CMakeLists.txt main.c

---

CMakeLists.txt

PROJECT(NEWHELLO)
ADD_SUBDIRECTORY(src)

src/main.c

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

int main(){
    sayHello();
    return 0;
}

src/CMakeLists.txt

#允许动态库路径使用相对路径
#https://cmake.org/cmake/help/v3.0/policy/CMP0015.html
cmake_policy(SET CMP0015 NEW)

#添加头文件路径
INCLUDE_DIRECTORIES(../../p4-library/lib)
#添加动态库路径
LINK_DIRECTORIES(../../p4-library/build/lib)

ADD_EXECUTABLE(main main.c)

#链接动态库
TARGET_LINK_LIBRARIES(main hello)

p6 cmake一些基本常量以及语法

CMakeLists.txt

anthor\CMakeLists.txt src1.c src2.c src3.c

src\CMakeLists.txt

build\

---

CMakeLists.txt

PROJECT(CONSTANT)
MESSAGE(STATUS "CMAKE_BINARY_DIR=" ${CMAKE_BINARY_DIR})
MESSAGE(STATUS "PROJECT_BINARY_DIR=" ${PROJECT_BINARY_DIR})
MESSAGE(STATUS "CONSTANT_BINARY_DIR=" ${CONSTANT_BINARY_DIR})

#当前CMakeLists.txt路径
MESSAGE(STATUS "CMAKE_CURRENT_SOURCE_DIR=" ${CMAKE_CURRENT_SOURCE_DIR})
MESSAGE(STATUS "CMAKE_CURRRENT_BINARY_DIR=" ${CMAKE_CURRRENT_BINARY_DIR})
MESSAGE(STATUS "CMAKE_CURRENT_LIST_FILE=" ${CMAKE_CURRENT_LIST_FILE})
MESSAGE(STATUS "CMAKE_CURRENT_LIST_LINE=" ${CMAKE_CURRENT_LIST_LINE})
MESSAGE(STATUS "CMAKE_MODULE_PATH=" ${CMAKE_MODULE_PATH})

ADD_SUBDIRECTORY(src)
ADD_SUBDIRECTORY(anthor)

src/CMakeLists.txt

MESSAGE(STATUS "THIS IS SRC")

MESSAGE(STATUS "CMAKE_BINARY_DIR=" ${CMAKE_BINARY_DIR})
MESSAGE(STATUS "PROJECT_BINARY_DIR=" ${PROJECT_BINARY_DIR})
MESSAGE(STATUS "CONSTANT_BINARY_DIR=" ${CONSTANT_BINARY_DIR})

MESSAGE(STATUS "CMAKE_SOURCE_DIR=" ${CMAKE_SOURCE_DIR})
MESSAGE(STATUS "PROJECT_SOURCE_DIR=" ${PROJECT_SOURCE_DIR})
MESSAGE(STATUS "CONSTANT_SOURCE_DIR=" ${CONSTANT_SOURCE_DIR})

MESSAGE(STATUS "CMAKE_CURRENT_SOURCE_DIR=" ${CMAKE_CURRENT_SOURCE_DIR})
MESSAGE(STATUS "CMAKE_CURRRENT_BINARY_DIR=" ${CMAKE_CURRRENT_BINARY_DIR})
MESSAGE(STATUS "CMAKE_CURRENT_LIST_FILE=" ${CMAKE_CURRENT_LIST_FILE})
MESSAGE(STATUS "CMAKE_CURRENT_LIST_LINE=" ${CMAKE_CURRENT_LIST_LINE})

anthor/CMakeLists.txt

MESSAGE(STATUS "THIS IS ANTHOR") 

#检测当前编译平台
#判断语句
IF(WIN32)
    MESSAGE(STATUS "SYSTEM IS WIN32")
ELSEIF(UNIX)
    MESSAGE(STATUS "SYSTEM IS UNIX")
ELSEIF(APPLE)
    MESSAGE(STATUS "SYSTEM IS APPLE")
ENDIF(WIN32)

#将当前文件夹的文件 添加到变量SRC_LIST
AUX_SOURCE_DIRECTORY(. SRC_LIST)

#循环语句
FOREACH(VAR ${SRC_LIST}) 
    MESSAGE(${VAR}) 
ENDFOREACH(VAR)

p7 使用FIND_PACKAGE查找模块

CMakeLists.txt

build/

src/CMakeLists.txt main.c

---

CMakeLists.txt

PROJECT(CURLTEST)
ADD_SUBDIRECTORY(src)

src/main.c

调用外部curl库 获取网页 并保存下来

#include <stdlib.h>
#include <unistd.h>

FILE *fp;
int write_data(void *ptr, size_t size, size_t nmemb, void *stream){
    int written = fwrite(ptr,size,nmemb,(FILE *)fp);
    return written;
}

int main(){
    const char *path = "./curl-test";
    const char *mode = "w";
    fp = fopen(path,mode);
    curl_global_init(CURL_GLOBAL_ALL);
    CURLcode res;
    CURL *curl = curl_easy_init();
    curl_easy_setopt(curl,CURLOPT_URL,"http://github.com/fishCoder");
    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, write_data);
    curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
    return 0; 
} 

src/CMakeLists.txt

ADD_EXECUTABLE(curltest main.c)

#查找curl库
FIND_PACKAGE(CURL)

IF(CURL_FOUND)
   INCLUDE_DIRECTORIES(${CURL_INCLUDE_DIR})
   TARGET_LINK_LIBRARIES(curltest ${CURL_LIBRARY})
ELSE(CURL_FOUND)
    #没有找到了 手动设置头文件和库
    MESSAGE(STATUS ”CURL library not found”)
    INCLUDE_DIRECTORIES(/usr/include) 
    TARGET_LINK_LIBRARIES(curltest curl)
ENDIF(CURL_FOUND)

p8 自己编写一个查找模块

CMakeLists.txt

build/

cmake/

src/

---

CMakeLists.txt

cmake_minimum_required(VERSION 3.0)
PROJECT(FINDHELLO)
#添加外部库搜索路径
SET(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
ADD_SUBDIRECTORY(src)

src/CMakeLists.txt

FIND_PACKAGE(HELLO)
IF(HELLO_FOUND)
    ADD_EXECUTABLE(hello main.c)
    INCLUDE_DIRECTORIES(${HELLO_INCLUDE_DIR})
    TARGET_LINK_LIBRARIES(hello ${HELLO_LIBRARY})
ELSE(HELLO_FOUND)
     MESSAGE(FATAL_ERROR "hello library not found")
ENDIF(HELLO_FOUND)

cmake/FindHELLO.cmake

cmake_policy(SET CMP0015 NEW)
#添加头文件搜索路径
FIND_PATH(HELLO_INCLUDE_DIR hello.h ../../p4-library/lib)
#添加库搜索路径
FIND_LIBRARY(HELLO_LIBRARY NAMES hello PATHS ../../p4-library/build/lib)

IF (HELLO_INCLUDE_DIR AND HELLO_LIBRARY)
   SET(HELLO_FOUND TRUE)
ENDIF (HELLO_INCLUDE_DIR AND HELLO_LIBRARY)
IF (HELLO_FOUND)
   IF (NOT HELLO_FIND_QUIETLY)
      MESSAGE(STATUS "Found Hello: ${HELLO_LIBRARY}")
ENDIF (NOT HELLO_FIND_QUIETLY)
ELSE (HELLO_FOUND)
   IF (HELLO_FIND_REQUIRED)
      MESSAGE(FATAL_ERROR "Could not find hello library")
   ENDIF (HELLO_FIND_REQUIRED)
ENDIF (HELLO_FOUND)