wspiapi.h uses _N conflicting with ctype.h

wspiapi.h uses _N conflicting with ctype.h

[Michael Enright]

Here's a reduction of a problem I had compiling v8:

#include <ctype.h>
#include "wspiapi.h"
char array[5];
__wspiapi_countof_helper(array);

The reduction isn't realistic but the problem is real.

On one hand, ctype.h uses _N and it is within its "rights" to do so as
ctype.h is part of the standard library. The statement that uses _N
initially is "#define _N 04", so _N enters the global space of defined
macros.

On the other hand the template __wspiapi_countof_helper uses _N as the
name of one of its parameters. This usage is in the domain of strings
that can be interpreted as references to macros by the preprocessor,
so the _N gets interpreted by the post-preprocessor phases as 04,
causing some distress.

So... the win32 headers are free to use
leading-underscore-capital-letter symbols or no?

Anyway, how can this be addressed?

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Re: wspiapi.h uses _N conflicting with ctype.h

[Corinna Vinschen]

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On Aug  3 04:17, Michael Enright wrote:
> Here's a reduction of a problem I had compiling v8:
> 
> #include <ctype.h>
> #include "wspiapi.h"
> char array[5];
> __wspiapi_countof_helper(array);
> 
> The reduction isn't realistic but the problem is real.
> 
> On one hand, ctype.h uses _N and it is within its "rights" to do so as
> ctype.h is part of the standard library. The statement that uses _N
> initially is "#define _N 04", so _N enters the global space of defined
> macros.
> 
> On the other hand the template __wspiapi_countof_helper uses _N as the
> name of one of its parameters. This usage is in the domain of strings
> that can be interpreted as references to macros by the preprocessor,
> so the _N gets interpreted by the post-preprocessor phases as 04,
> causing some distress.
> 
> So... the win32 headers are free to use
> leading-underscore-capital-letter symbols or no?

It's unfortunate, but with their right, just like the std headers.

> Anyway, how can this be addressed?

The best result would be if you (or we) could convince the mingw-w64
guys not to use _N.  Jon?  Any chance you could apply a patch to use
_n with lower case n?

For the time being, you can push/pop the clashing macros prior to
including the problematic header(s):

  #include <ctype.h>
  #pragma push_macro ("_N")
  #undef _N
  #include <wspiapi.h>
  #pragma pop_macro("_N")


Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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Re: wspiapi.h uses _N conflicting with ctype.h

[JonY]

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On 8/3/2015 21:46, Corinna Vinschen wrote:
> 
> The best result would be if you (or we) could convince the mingw-w64
> guys not to use _N.  Jon?  Any chance you could apply a patch to use
> _n with lower case n?
> 
> For the time being, you can push/pop the clashing macros prior to
> including the problematic header(s):
> 
>   #include <ctype.h>
>   #pragma push_macro ("_N")
>   #undef _N
>   #include <wspiapi.h>
>   #pragma pop_macro("_N")
> 
> 

OK, I'll see to this.




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