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Re: [WIP] mingw64 related changes to Cygwin configure and other assorted files with departed w32api/mingw
On Tue, Nov 13, 2012 at 07:19:08PM +0100, Corinna Vinschen wrote:
>On Nov 13 12:39, Christopher Faylor wrote:
>> On Tue, Nov 13, 2012 at 10:33:01AM +0100, Corinna Vinschen wrote:
>> >I would also like to keep the ifndef/define brackets in
>> >the headers since
>> >
>> > #ifndef _CYGWIN_IF_H_
>> > #define _CYGWIN_IF_H_
>> >
>> >can be tested for in other headers while #pragma once can not.
>>
>> I think that testing for "BLAH_DECLARED" for individual definitions is a
>> much better way to see if something is defined than relying on an
>> implementation detail like "_CYGWIN_IF_H".
>
>Sure.
>
>This might not be of much interest for the headers in the include/cygwin
>subdir, but there are applications out there which test for such header
>defines, and there are also applications using system-specific headers
>liberally. Out of curiosity I had a look and none of the Linux/glibc
>headers seem to use #pragma once either for some reason.
I do see some '#pragma once's in my /usr/include tree but they don't
come from glibc. Maybe it's a conscious decision not to use this or
maybe nobody could be bothered to make the change. I don't see any
discussion in the libc-alpha mailing list about this but I only spent 10
seconds googling.
>An alternative might be something like
>
> #pragma once
> #define _CYGWIN_IF_H_
>
>It would introduce the new pragma and keep the definition available.
Yeah, that would work but you're still adding a define that shouldn't
really be used to the cygnosphere.
cgf