How to partially disabling cmake C/C++ custom compiler checking

问题

I am trying to do some crosscompilation using cmake. Some are easy with all the examples on Internet, I managed to crosscompile my library on Linux (x86 and ARM), Windows and Android. But now I would like to do it on a custom platform.

The process I need to achieve:

Sourcing my environment (this destroy all previous bash classic environment)
Compile with cmake
Execute what I want

But Cmake is testing for symbols in my custom C/C++ libraries which make my library unable to compile. The errors I have are that cmake some versions of GLIBCXX and CXXABI (no C issues) but not all of them.

Is there a way to make cmake ok with it ?

EDIT:

I tried using:

set(CMAKE_C_COMPILER_WORKS TRUE)
set(CMAKE_CXX_COMPILER_WORKS TRUE)

And with:

include(CMakeForceCompiler)
...
cmake_force_c_compiler(${ENV_PATH}/bin/${CC})
cmake_force_cxx_compiler(${ENV_PATH}/bin/${CXX})

But cmake is still checking for symbols.

回答1:

Without having your environment nor the error message it's not easy to tell the actual root cause but here are two of the common causes and respective fixes:

If you don't have a complete toolchain file created for your custom environment - so CMake can't link a simple test program - you can try the relatively new (version 3.6) global CMake variable named CMAKE_TRY_COMPILE_TARGET_TYPE.

So just add the following:
```
set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
```
Then CMake would just try to build a static library.
To have only the most common GCC compiler variables set and have only some basic checks, try:
```
SET(CMAKE_SYSTEM_NAME Generic)
```
See CMake Cross Compiling: Setting up the system and toolchain:

If your target is an embedded system without OS set CMAKE_SYSTEM_NAME to "Generic"

References

CMake AMRCC + custom linker
cmake cross-compile with specific linker doesn't pass arguments to armlink

回答2:

Commandline:

    cmake ... \
    -DCMAKE_C_COMPILER_FORCED=TRUE \
    -DCMAKE_CXX_COMPILER_FORCED=TRUE

CMakeLists.txt

    ...
    set(CMAKE_C_COMPILER_FORCED TRUE)
    set(CMAKE_CXX_COMPILER_FORCED TRUE)
    ...

Works for me.

来源：https://stackoverflow.com/questions/38700198/how-to-partially-disabling-cmake-c-c-custom-compiler-checking

标签

c++

compilation

cmake