使用 CMake 设置 CFLAGS 和 CXXFLAGS 选项

我只是想调试一些运行在 Linux 上的代码，我需要一个调试版本(-O0 -ggdb)。所以我把这些东西加入到我的 CMakeLists.txt中:

set(CMAKE_BUILD_TYPE DEBUG)
set(CMAKE_C_FLAGS "-O0 -ggdb")
set(CMAKE_C_FLAGS_DEBUG "-O0 -ggdb")
set(CMAKE_C_FLAGS_RELEASE "-O0 -ggdb")
set(CMAKE_CXX_FLAGS "-O0 -ggdb")
set(CMAKE_CXX_FLAGS_DEBUG "-O0 -ggdb")
set(CMAKE_CXX_FLAGS_RELEASE "-O0 -ggdb")

当我尝试编译时，我使用 make VERBOSE=1打开详细程序 我观察了输出，像这样

... /usr/bin/c++ -D_BSD_SOURCE **-O0 -ggdb** -Wnon-virtual-dtor
-Wno-long-long -ansi -Wundef -Wcast-align -Wchar-subscripts -Wall -W
-Wpointer-arith -Wformat-security -fno-exceptions -DQT_NO_EXCEPTIONS
-fno-check-new -fno-common -Woverloaded-virtual -fno-threadsafe-statics
-fvisibility=hidden -fvisibility-inlines-hidden **-g -O2**
-fno-reorder-blocks -fno-schedule-insns -fno-inline ...

显然代码是用 "-g -O2"编译的，这不是我想要的。如何强制它只使用 "-O0 -ggdb"？

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最佳答案

You need to set the flags after the project command in your CMakeLists.txt.

Also, if you're calling include(${QT_USE_FILE}) or add_definitions(${QT_DEFINITIONS}), you should include these set commands after the Qt ones since these would append further flags. If that is the case, you maybe just want to append your flags to the Qt ones, so change to e.g.

set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O0 -ggdb")
小开

You must change the cmake C/CXX default FLAGS .

According to CMAKE_BUILD_TYPE={DEBUG/MINSIZEREL/RELWITHDEBINFO/RELEASE} put in the main CMakeLists.txt one of :

For C

set(CMAKE_C_FLAGS_DEBUG "put your flags")
set(CMAKE_C_FLAGS_MINSIZEREL "put your flags")
set(CMAKE_C_FLAGS_RELWITHDEBINFO "put your flags")
set(CMAKE_C_FLAGS_RELEASE "put your flags")

For C++

set(CMAKE_CXX_FLAGS_DEBUG "put your flags")
set(CMAKE_CXX_FLAGS_MINSIZEREL "put your flags")
set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "put your flags")
set(CMAKE_CXX_FLAGS_RELEASE "put your flags")

This will override the values defined in CMakeCache.txt

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On Unix systems, for several projects, I added these lines into the CMakeLists.txt and it was compiling successfully because base (/usr/include) and local includes (/usr/local/include) go into separated directories:

set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -I/usr/local/include -L/usr/local/lib")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -I/usr/local/include")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -L/usr/local/lib")

It appends the correct directory, including paths for the C and C++ compiler flags and the correct directory path for the linker flags.

Note: C++ compiler (c++) doesn't support -L, so we have to use CMAKE_EXE_LINKER_FLAGS

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The easiest solution working fine for me is this:

export CFLAGS=-ggdb
export CXXFLAGS=-ggdb

CMake will append them to all configurations' flags. Just make sure to clear CMake cache.


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