Gisle Vanem

2017-11-02 14:10:41 UTC

Hello list.

I'm trying to use Gnulib's <math.h> from clang-cl C++

compiler. I have no problems with pure C with either clang-cl

or MSVC. But in C++ I get endless troubles with errors like these:

f:/MingW32/src/gnu/gnulib/lib\math.h(2397,36): error: functions that

differ only in their return type cannot be overloaded

_GL_MATH_CXX_REAL_FLOATING_DECL_2 (signbit)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~

Thanks to the excellent 'clang-format' program, I was able to generate

this preprocessed output:

// from MSVC and UCRT's <corecrt_math.h>:

inline bool signbit(float _X) throw()

{

return _fdsign(_X) != 0;

}

inline bool signbit(double _X) throw()

{

return _dsign(_X) != 0;

}

inline bool signbit(long double _X) throw()

{

return _ldsign(_X) != 0;

}

// and then from Gnulib's <math.h>:

inline int signbit(float f)

{

return _gl_cxx_signbitf(f);

}

inline int signbit(double d)

{

return _gl_cxx_signbitd(d);

}

inline int signbit(long double l)

{

return _gl_cxx_signbitl(l);

}

I'm getting these error even without a 'REPLACE_SIGNBIT=1'.

And I fail to see how to prevent the above from getting into

<math.h>.

I'm not C++ export, but would imagine that 'int' and 'bool'

are different types. Or does the 'throw()' have anything to do with

this error? Any hints please?

PS. I've tried clang-cl v3.9.0 and 5.0.0 with the same result.

I'm trying to use Gnulib's <math.h> from clang-cl C++

compiler. I have no problems with pure C with either clang-cl

or MSVC. But in C++ I get endless troubles with errors like these:

f:/MingW32/src/gnu/gnulib/lib\math.h(2397,36): error: functions that

differ only in their return type cannot be overloaded

_GL_MATH_CXX_REAL_FLOATING_DECL_2 (signbit)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~

Thanks to the excellent 'clang-format' program, I was able to generate

this preprocessed output:

// from MSVC and UCRT's <corecrt_math.h>:

inline bool signbit(float _X) throw()

{

return _fdsign(_X) != 0;

}

inline bool signbit(double _X) throw()

{

return _dsign(_X) != 0;

}

inline bool signbit(long double _X) throw()

{

return _ldsign(_X) != 0;

}

// and then from Gnulib's <math.h>:

inline int signbit(float f)

{

return _gl_cxx_signbitf(f);

}

inline int signbit(double d)

{

return _gl_cxx_signbitd(d);

}

inline int signbit(long double l)

{

return _gl_cxx_signbitl(l);

}

I'm getting these error even without a 'REPLACE_SIGNBIT=1'.

And I fail to see how to prevent the above from getting into

<math.h>.

I'm not C++ export, but would imagine that 'int' and 'bool'

are different types. Or does the 'throw()' have anything to do with

this error? Any hints please?

PS. I've tried clang-cl v3.9.0 and 5.0.0 with the same result.

--

--gv

--gv