当使用CMake构建时,可以设置C和C++编译器。此示例与hello-cmake示例相同,只是它显示了将编译器从默认的GCC更改为clang的最基本方法。
本教程中的文件如下:
$ tree
.
├── CMakeLists.txt
├── main.cpp
-
[CMakeLists.txt] - 包含要运行的CMake命令。
# Set the minimum version of CMake that can be used # To find the cmake version run # $ cmake --version cmake_minimum_required(VERSION 3.5) # Set the project name project (hello_cmake) # Add an executable add_executable(hello_cmake main.cpp)
-
[main.cpp] - 一个简单的“Hello World”C++文件。
#include <iostream> int main(int argc, char *argv[]) { std::cout << "Hello CMake!" << std::endl; return 0; }
CMake公开了用于控制编译和链接代码的程序的选项。这些程序包括:
- CMAKE_C_COMPILER - 用于编译c代码的程序.
- CMAKE_CXX_COMPILER - 用于编译c++代码的程序.
- CMAKE_LINKER - 用于链接二进制文件的程序.
Note | 在本例中,clang-3.6是通过命令sudo apt-get install clang-3.6 安装的。 |
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Note | 这是调用clang的最基本、最简单的方式。未来的示例将展示调用编译器的更好方法。 |
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如第6节示例中所述,你可以使用cmake gui或通过命令行来设置CMake选项。
下面是通过命令行向编译器传递参数的示例。
cmake .. -DCMAKE_C_COMPILER=clang-3.6 -DCMAKE_CXX_COMPILER=clang++-3.6
在设置这些选项之后,当你运行make时,clang将用于编译你的二进制文件。这可以从make输出中的以下几行看出。
/usr/bin/clang++-3.6 -o CMakeFiles/hello_cmake.dir/main.cpp.o -c /home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/main.cpp
Linking CXX executable hello_cmake
/usr/bin/cmake -E cmake_link_script CMakeFiles/hello_cmake.dir/link.txt --verbose=1
/usr/bin/clang++-3.6 CMakeFiles/hello_cmake.dir/main.cpp.o -o hello_cmake -rdynamic
下面是示例输出:
$ mkdir build.clang
$ cd build.clang/
$ cmake .. -DCMAKE_C_COMPILER=clang-3.6 -DCMAKE_CXX_COMPILER=clang++-3.6
-- The C compiler identification is Clang 3.6.0
-- The CXX compiler identification is Clang 3.6.0
-- Check for working C compiler: /usr/bin/clang-3.6
-- Check for working C compiler: /usr/bin/clang-3.6 -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working CXX compiler: /usr/bin/clang++-3.6
-- Check for working CXX compiler: /usr/bin/clang++-3.6 -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Configuring done
-- Generating done
-- Build files have been written to: /home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang
$ make VERBOSE=1
/usr/bin/cmake -H/home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang -B/home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang --check-build-system CMakeFiles/Makefile.cmake 0
/usr/bin/cmake -E cmake_progress_start /home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang/CMakeFiles /home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang/CMakeFiles/progress.marks
make -f CMakeFiles/Makefile2 all
make[1]: Entering directory `/home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang'
make -f CMakeFiles/hello_cmake.dir/build.make CMakeFiles/hello_cmake.dir/depend
make[2]: Entering directory `/home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang'
cd /home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang /home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang /home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang /home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang /home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang/CMakeFiles/hello_cmake.dir/DependInfo.cmake --color=
Dependee "/home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang/CMakeFiles/hello_cmake.dir/DependInfo.cmake" is newer than depender "/home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang/CMakeFiles/hello_cmake.dir/depend.internal".
Dependee "/home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang/CMakeFiles/CMakeDirectoryInformation.cmake" is newer than depender "/home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang/CMakeFiles/hello_cmake.dir/depend.internal".
Scanning dependencies of target hello_cmake
make[2]: Leaving directory `/home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang'
make -f CMakeFiles/hello_cmake.dir/build.make CMakeFiles/hello_cmake.dir/build
make[2]: Entering directory `/home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang'
/usr/bin/cmake -E cmake_progress_report /home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang/CMakeFiles 1
[100%] Building CXX object CMakeFiles/hello_cmake.dir/main.cpp.o
/usr/bin/clang++-3.6 -o CMakeFiles/hello_cmake.dir/main.cpp.o -c /home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/main.cpp
Linking CXX executable hello_cmake
/usr/bin/cmake -E cmake_link_script CMakeFiles/hello_cmake.dir/link.txt --verbose=1
/usr/bin/clang++-3.6 CMakeFiles/hello_cmake.dir/main.cpp.o -o hello_cmake -rdynamic
make[2]: Leaving directory `/home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang'
/usr/bin/cmake -E cmake_progress_report /home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang/CMakeFiles 1
[100%] Built target hello_cmake
make[1]: Leaving directory `/home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang'
/usr/bin/cmake -E cmake_progress_start /home/matrim/workspace/cmake-examples/01-basic/I-compiling-with-clang/build.clang/CMakeFiles 0
$ ./hello_cmake
Hello CMake!
原文作者:橘崽崽啊