如何应用不同的编译器选项为不同的编译器在cmake？ [英] How to apply different compiler options for different compilers in cmake?

问题描述

我目前正在使用cmake来构建一些项目，主要平台是Visual C ++，MinGW GCC和Linux GCC。当使用GCC构建时，我需要指定 -Wno-invalid-offsetof 编译器选项。

如下：

  if（$ {CMAKE_GENERATOR}MATCHES^ Visual Studio
 OR $ {CMAKE_GENERATOR}MATCHES^ NMake
）
 set（CPPLIB_COMPILER_OPTS）
 else（）
 set（CPPLIB_COMPILER_OPTS-Wno-invalid-offsetof）
 endif（）
 
 ... 
 
 set_target_properties（sh_core PROPERTIES COMPILE_FLAGS$ {CPPLIB_COMPILER_OPTS}）
＃为所有目标重复
  

这样工作，但假设除了visual studio之外的所有生成器都将使用gcc构建显然是不安全的。首先，Borland编译器有IIRC发生器。更重要的是，使用make不总是意味着使用gcc。

其他编译器我可能使用的是llvm-gcc和clang。幸运的是，我认为即使clang支持gcc兼容的选项。但是这个逻辑只有在相关代码永远不会被释放时才有效。

Cmake似乎检查可用的编译器，并为该编译器生成一个makefile问题 - 为什么不是至少可以选择直接构建项目，而不需要像make这样的中间人。）

在这种情况下，我是希望能够在我的CMakeLists.txt文件中直接测试gcc。到目前为止，我找不到一个合适的变量来测试或其他任何明显的解决方案。

这是否可能？

p>而不是测试如果Windows然后这样做，测试如果-Wno-invalid-offsetof标志工作，然后使用它。您可以使用CheckCCompilerFlag模块，例如：

  include（CheckCCompilerFlag）
 check_c_compiler_flag（-Wno-invalid -offsetof HAS_NO_INVALID_OFFSETOF）
 if（HAS_NO_INVALID_OFFSETOF）
 set（CMAKE_C_FLAGS$ {CMAKE_C_FLAGS} -Wno-invalid-offsetof）
 endif（）
  
 
 
 
对于C ++，有一个类似的CheckCXXCompilerFlag和一个 check_cxx_compiler_flag（flag var） > 
I'm currently working on using cmake to build some projects, with the main platforms being Visual C++, MinGW GCC and Linux GCC. When building with GCC, I need to specify the -Wno-invalid-offsetof compiler option.

My current fix is as follows...
if (   "${CMAKE_GENERATOR}" MATCHES "^Visual Studio"
    OR "${CMAKE_GENERATOR}" MATCHES "^NMake"
   )
    set (CPPLIB_COMPILER_OPTS "")
else ()
    set (CPPLIB_COMPILER_OPTS "-Wno-invalid-offsetof")
endif ()

...

set_target_properties(sh_core PROPERTIES COMPILE_FLAGS "${CPPLIB_COMPILER_OPTS}")
# repeated for all targets
This works, but assuming that all generators other than the visual studio ones will build with gcc is obviously unsafe. For a start, there are IIRC generators for Borland compilers. More importantly, using make doesn't always mean using gcc.

Other compilers I'm likely to use are llvm-gcc and clang. Fortunately, I think even clang supports gcc-compatible options. But this logic is only good for as long as the relevant code is never released.

Cmake appears to check for available compilers and generate a makefile specifically for that compiler (raising the question - why not at least have the option of building the project directly, without the need for a middle-man like make?).

That being the case, I was hoping to be able to test directly for gcc in my CMakeLists.txt files. So far, though, I can't find an appropriate variable to test or any other obvious solution.

Is this possible?
解决方案
To create a portable build system, it is best to not test for platforms, but to test for features.

Instead of testing "if Windows then do this", test for "if the -Wno-invalid-offsetof flag works then use it". You can do that with the CheckCCompilerFlag module, for example:
include(CheckCCompilerFlag)
check_c_compiler_flag(-Wno-invalid-offsetof HAS_NO_INVALID_OFFSETOF)
if (HAS_NO_INVALID_OFFSETOF)
    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-invalid-offsetof")
endif()
For C++ there is a similar CheckCXXCompilerFlag with a check_cxx_compiler_flag(flag var) command.

                        
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