CMake 无法检测到 trival 文件上的 C 编译器

Question

我有一个非常大的项目，我正在尝试从 GNU make 迁移到 cmake。因此，我认为拥有包含各种变量的中间文件是一个好方法。

由于我刚刚开始，这就是我对 top_directory/vars/CMakeLists.txt 的内容：

cmake_minimum_required(VERSION 2.8)

set(VARIABLE "value")

这样，在另一个文件夹中，我可以将此行添加到 CMakeLists.txt 中：

add_subdirectory(top_directory/vars)

但是，当尝试在 top_directory/vars/CMakeLists.txt 上运行 cmake 时，我收到以下错误：

me@host:/tmp>cmake .
-- The C compiler identification is unknown
-- The CXX compiler identification is GNU 7.3.1
-- Check for working C compiler: /usr/bin/g++
-- Check for working C compiler: /usr/bin/g++ -- broken
CMake Error at /usr/share/cmake/Modules/CMakeTestCCompiler.cmake:52 (message):
  The C compiler

    "/usr/bin/g++"

  is not able to compile a simple test program.

  It fails with the following output:

    Change Dir: /tmp/CMakeFiles/CMakeTmp

    Run Build Command:"/usr/bin/gmake" "cmTC_607e9/fast"
    /usr/bin/gmake -f CMakeFiles/cmTC_607e9.dir/build.make CMakeFiles/cmTC_607e9.dir/build
    gmake[1]: Entering directory '/tmp/CMakeFiles/CMakeTmp'
    Building C object CMakeFiles/cmTC_607e9.dir/testCCompiler.c.o
    /usr/bin/g++    -o CMakeFiles/cmTC_607e9.dir/testCCompiler.c.o   -c /tmp/CMakeFiles/CMakeTmp/testCCompiler.c
    /tmp/CMakeFiles/CMakeTmp/testCCompiler.c:2:3: error: #error "The CMAKE_C_COMPILER is set to a C++ compiler"
     # error "The CMAKE_C_COMPILER is set to a C++ compiler"
       ^~~~~
    gmake[1]: *** [CMakeFiles/cmTC_607e9.dir/build.make:66: CMakeFiles/cmTC_607e9.dir/testCCompiler.c.o] Error 1
    gmake[1]: Leaving directory '/tmp/CMakeFiles/CMakeTmp'
    gmake: *** [Makefile:126: cmTC_607e9/fast] Error 2




  CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
  CMakeLists.txt


-- Configuring incomplete, errors occurred!
See also "/tmp/CMakeFiles/CMakeOutput.log".
See also "/tmp/CMakeFiles/CMakeError.log".

现在我可以通过添加

-DCMAKE_C_COMPILER=gcc

来强制它，但这确实破坏了可移植性方面。

所以我的问题是：这是制作“可变”CMake 文件的正确方法吗？为什么 CMake 错误地检测到我的 C 编译器？

有用信息：

cmake --version
cmake version 3.11.1
CMake suite maintained and supported by Kitware (kitware.com/cmake).

gcc --version
gcc (SUSE Linux) 7.3.1 20180323 [gcc-7-branch revision 258812]
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

如果我可以提供任何其他信息，请告诉我。

Answer 1

使用

cmake -DCMAKE_C_COMPILER=/..../lnx64/gcc-8.3.0/bin/gcc -DCMAKE_CXX_COMPILER=/..../lnx64/gcc-8.3.0/bin/g++ ..