[Python-Dev] use of #pragma GCC system_header to suppress _XOPEN_SOURCE warnings (original) (raw)

"Martin v. Löwis" martin at v.loewis.de
Thu Aug 5 23:40:56 CEST 2004

Skip Montanaro wrote:

At work the goal for our C++ build environment is "no warnings with gcc -Wall". We are not there yet (and thankfully I am not a participant in that particular holy grail), but those involved in that effort encountered a warning the other day generated because XOPENSOURCE is defined in pyconfig.h. Unfortunately GCC also defines it, so a "macro redefined" warning is emitted when compiling with GCC and including Python.h.

That is not true. GCC does not define that macro, on any platform.

Some system header may define it, though. I believe this is a bug in the system - the macro should be defined in the application. What system are you referring to, and where does that define _XOPEN_SOURCE? Is that definition conditional?

Perhaps adding

#pragma GCC systemheader to pyconfig.h.in would be acceptable though.

I'd prefer to solve the problem properly. If the system defines something, and we define it differently, this is a problem, and deserves a warning. We should find out why that is, and what can be done about. Perhaps we should not define _XOPEN_SOURCE on that platform until the vendor fixes the platform bug, or we should aim at defining it the same way the vendor does.

Silencing errors is a risky thing.

Regards, Martin

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