upadte site

src/content/blog/cmake_intro.md

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+---
+title: "Cmake简单使用"
+author: suo yuan
+pubDatetime: 2024-05-12T14:23:43.439Z
+featured: false
+draft: false
+tags:
+  - Cpp notes
+  - intro
+description: "本次更换博客框架的相关记录"
+---
+
+# Cmake 简单使用
+
+由于想要编写一个C++的项目，所以开始学习`cmake`管理项目的编译工作。我这里会把 **src** 和 **include** 分开，并且尝试使用[Google test](https://github.com/google/googletest)做一些项目的简单测试。
+
+```bash
+$ tree -L 3
+.
+├── CMakeLists.txt
+├── compile_commands.json
+├── src
+│   ├── include
+│   │   ├── cppcurl.h
+│   │   ├── errmsg.h
+│   │   └── os-detect.h
+│   ├── main.c
+│   ├── main.cpp
+│   └── os-detect.cpp
+├── test
+│   ├── CMakeLists.txt
+│   └── main_test.cpp
+└── third_party
+    ├── CMakeLists.txt
+    └── googletest
+        ├── BUILD.bazel
+        ├── ci
+        ├── CMakeLists.txt
+        ├── CONTRIBUTING.md
+        ├── CONTRIBUTORS
+        ├── docs
+        ├── fake_fuchsia_sdk.bzl
+        ├── googlemock
+        ├── googletest
+        ├── googletest_deps.bzl
+        ├── LICENSE
+        ├── MODULE.bazel
+        ├── README.md
+        ├── WORKSPACE
+        └── WORKSPACE.bzlmod
+```
+
+上面这个就是我项目的基础结构，**src** 存放项目的源代码，**src/include** 从存放一些自定义的头文件，**test** 目录存放用于开发测试的代码文件，**third_party** 目录存放第三方库文件。
+
+我根目录的 **CMakeLists.txt** 文件的内容是：
+
+```CMakeLists
+cmake_minimum_required(VERSION 3.11)
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON) # For clang-tidy.
+set(CMAKE_CXX_STANDARD 20) # Compile as C++20.
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+project(project)
+
+if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
+        message(STATUS "Setting build type to `Debug` as none was specified.")
+        set(CMAKE_BUILD_TYPE "Debug")
+endif()
+
+if(EMSCRIPTEN)
+        add_compile_options(-fexceptions)
+        add_link_options(-fexceptions)
+endif()
+
+file(TO_CMAKE_PATH "${PROJECT_BINARY_DIR}/CMakeLists.txt" PATH_TO_CMAKELISTS_TXT)
+
+if(EXISTS "${PATH_TO_CMAKELISTS_TXT}")
+        message(FATAL_ERROR "Run CMake from a build subdirectory! \"mkdir build ; cd build ; cmake ..\" \
+    Some junk files were created in this folder (CMakeCache.txt, CMakeFiles); you should delete those.")
+endif()
+
+# Compiler flags.
+set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -Wall -Wextra -Werror")
+set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -Wno-unused-parameter -Wno-attributes") # TODO: remove
+set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -O0 -ggdb -fsanitize=${BUSTUB_SANITIZER} -fno-omit-frame-pointer -fno-optimize-sibling-calls")
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+
+message(STATUS "CMAKE_CXX_FLAGS: ${CMAKE_CXX_FLAGS}")
+message(STATUS "CMAKE_CXX_FLAGS_DEBUG: ${CMAKE_CXX_FLAGS_DEBUG}")
+message(STATUS "CMAKE_EXE_LINKER_FLAGS: ${CMAKE_EXE_LINKER_FLAGS}")
+message(STATUS "CMAKE_SHARED_LINKER_FLAGS: ${CMAKE_SHARED_LINKER_FLAGS}")
+
+enable_testing()
+
+add_executable(project "src/main.cpp")
+set(RB_THIRD_PARTY_INCLUDE_DIR
+        ${PROJECT_SOURCE_DIR}/third_party
+)
+set(
+    RB_SRC_INCLUDE_DIR
+    ${PROJECT_SOURCE_DIR}/src/include
+)
+include_directories(${RB_SRC_INCLUDE_DIR} ${RB_THIRD_PARTY_INCLUDE_DIR})
+
+add_subdirectory(third_party)
+add_subdirectory(test)
+```
+
+**third_party** 目录下的 **CMakeLists.txt** 只又一行内容，就是为了加入 **googletest**
+
+```CMakeLists
+add_subdirectory(googletest)
+```
+
+**test** 目录下还有些东西，因为遇到额外添加 **googletest** 中的include到编译过程中，还要启用testing
+
+```CMakeLists
+cmake_minimum_required(VERSION 3.11)
+
+set(TEST_TARGET_NAME main_test)
+
+file(GLOB_RECURSE TEST_SOURCES "*.cpp")
+
+add_executable(${TEST_TARGET_NAME} ${TEST_SOURCES})
+
+include_directories(${PROJECT_SOURCE_DIR}/third_party/googletest/googletest/include)
+
+target_link_libraries(${TEST_TARGET_NAME} gtest gtest_main)
+
+set_target_properties(${TEST_TARGET_NAME} PROPERTIES
+    CXX_STANDARD 20
+    CXX_STANDARD_REQUIRED ON
+)
+
+add_test(NAME ${TEST_TARGET_NAME} COMMAND ${TEST_TARGET_NAME})
+```
+
+**test** 目录下的示例程序:
+
+```cpp
+#include "gtest/gtest.h"
+
+// 定义一个测试用例
+TEST(ExampleTest, Addition) {
+    // 在这里编写测试逻辑
+    int result = 1 + 2;
+    // 使用 Google Test 提供的断言来验证结果是否符合预期
+    EXPECT_EQ(result, 3); // 期望结果为 3
+}
+
+// 可以定义更多的测试用例
+
+// main 函数用于运行所有测试用例
+auto main(int argc, char **argv) -> int {
+    // 初始化 Google Test 框架
+    ::testing::InitGoogleTest(&argc, argv);
+    // 运行所有测试用例，并返回测试结果
+    return RUN_ALL_TESTS();
+}
+```
+
+在项目的根目录下，执行下边的语句:
+
+```bash
+$ cmake --build build --config Debug --target all -j `nproc`
+[  8%] Building CXX object third_party/googletest/googletest/CMakeFiles/gtest.dir/src/gtest-all.cc.o
+[ 16%] Building CXX object CMakeFiles/ReleaseButler.dir/src/main.cpp.o
+[ 25%] Linking CXX executable ReleaseButler
+[ 25%] Built target ReleaseButler
+[ 33%] Linking CXX static library ../../../lib/libgtest.a
+[ 33%] Built target gtest
+[ 41%] Building CXX object third_party/googletest/googletest/CMakeFiles/gtest_main.dir/src/gtest_main.cc.o
+[ 50%] Building CXX object third_party/googletest/googlemock/CMakeFiles/gmock.dir/src/gmock-all.cc.o
+[ 58%] Linking CXX static library ../../../lib/libgtest_main.a
+[ 58%] Built target gtest_main
+[ 66%] Building CXX object test/CMakeFiles/main_test.dir/main_test.cpp.o
+[ 75%] Linking CXX static library ../../../lib/libgmock.a
+[ 75%] Built target gmock
+[ 83%] Building CXX object third_party/googletest/googlemock/CMakeFiles/gmock_main.dir/src/gmock_main.cc.o
+[ 91%] Linking CXX executable main_test
+[ 91%] Built target main_test
+[100%] Linking CXX static library ../../../lib/libgmock_main.a
+[100%] Built target gmock_main
+```
+
+这样在 **build/test** 目录下就会生成一个用于测试的程序。执行即可
+
+```bash
+$ ./build/test/main_test
+[==========] Running 1 test from 1 test suite.
+[----------] Global test environment set-up.
+[----------] 1 test from ExampleTest
+[ RUN      ] ExampleTest.Addition
+[       OK ] ExampleTest.Addition (0 ms)
+[----------] 1 test from ExampleTest (0 ms total)
+
+[----------] Global test environment tear-down
+[==========] 1 test from 1 test suite ran. (0 ms total)
+[  PASSED  ] 1 test.
+```
+
+这里有一个问题，我使用的是Visual Studio Code写代码，用clangd插件提高C/C++的编程，我一开始用`ln -s`给 **build/compile_commands.json** 文件在根目录建一个软链接，但是clangd的没有成功解析出 **test/main_test.cpp** 文件的头文件位置，后来我安装了bear，特地`bear -- cmake`生成了一个 **compile_commands.json** 才成功解析