[CMake] CHECK_CXX_ACCEPTS_FLAG delieverts wrong result

[Fetzer, Andreas]

Hi,

thanks for your answer. But the problem is that this flag is accepted although the clang compiler does not accept it. This leads to a build error.
My question is why the CHECK_CXX_ACCEPTS_FLAG marco does not recognize that the flag is not supported by my compiler.

Andreas


On Sep 24, 2013, at 7:13 PM, Hendrik Sattler <post at hendrik-sattler.de> wrote:

> 
> 
> "Fetzer, Andreas" <a.fetzer at Dkfz-Heidelberg.de> schrieb:
>> Hi,
>> 
>> I am using Mac OS X 10.7 with Apple clang version 3.1. At the moment
>> our build fails due to an unknown compiler flag:
>> 
>> error: unknown warning option '-Wstrict-null-sentinel'
>> [-Werror,-Wunknown-warning-option]
>> 
>> Although we are checking whether the flag is accepted by the selected
>> compiler. When I use the following statement:
>> 
>> 
>>   CHECK_CXX_ACCEPTS_FLAG(${_cxxflag} HAS_FLAG)
>> 
>>   if(NOT HAS_FLAG)
>> 
>>     message("Flag check failure ${_cxxflag}")
>> 
>>   else()
>> 
>>     message("Flag ${_cxxflag} accepted")
>> 
>>   endif()
>> 
>> Cmake tells me that the '-Wstrict-null-sentinel' flag is accepted. Is
>> this a bug in Cmake or am I doing something wrong?
>> I use Cmake 2.8.8
>> 
>> Thanks in advance!
>> 
>> Best regards
>> Andreas
>> 
>> 
>> 
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> 
> Hi, 
> 
> the clang error message already tells you what other option are needed so that clang rejects unknown -W options: -Werror
> 
> HS
> 
> 
> --
> 
> Powered by www.kitware.com
> 
> Please keep messages on-topic and check the CMake FAQ at: http://www.cmake.org/Wiki/CMake_FAQ
> 
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> 
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