Boost C++ Libraries: Ticket #7389: __STDC_LIMIT_MACROS can be redefined by boost when using mingw32

component changed; owner set

viboes — Tue, 18 Sep 2012 16:52:44 GMT

owner set to John Maddock
component None → config

attachment set

Wed, 03 Oct 2012 09:06:58 GMT

attachment → win32.hpp.patch

A patch

description changed

viboes — Mon, 29 Oct 2012 02:25:51 GMT

description modified (diff)

John Maddock — Tue, 19 Feb 2013 13:15:43 GMT

(In [82998]) Fix for STDC_LIMIT_MACROS already defined. Refs #7389.

viboes — Tue, 19 Feb 2013 22:02:41 GMT

Why do we need to define

__STDC_LIMIT_MACROS

What happens if the user include the files using this macro before the boost config files?

anonymous — Wed, 20 Feb 2013 09:08:24 GMT

What happens if the user include the files using this macro before the boost config files?

We have to fall back to code that doesn't depend on UINT8_MAX etc being defined. Ideally if stdint.h is included twice - once without __STDC_LIMIT_MACROS and then again with it, it will do the right thing and fill in the definitions it missed out the first time. Not all implementations do that though :-(

viboes — Wed, 20 Feb 2013 18:08:02 GMT

Replying to anonymous:

What happens if the user include the files using this macro before the boost config files?

We have to fall back to code that doesn't depend on UINT8_MAX etc being defined. Ideally if stdint.h is included twice - once without __STDC_LIMIT_MACROS and then again with it, it will do the right thing and fill in the definitions it missed out the first time. Not all implementations do that though :-(

Isn't stdint.h protected for multiple inclusions?

anonymous — Wed, 20 Feb 2013 18:42:38 GMT

Isn't stdint.h protected for multiple inclusions?

Maybe!

In C99 it defines different things depending on whether __STDC_LIMIT_MACROS is defined or not, so rather like assert.h with NDEBUG it should really "correct itself" each time it's included depending upon the value of the macro. Thankfully C++11 does the sane thing and just requires that the limit macros are always defined.

Either way, we should really try to get the system defined limits macros if we can, just because we can't be certain of getting them every time, isn't a reason not to try.

viboes — Thu, 21 Feb 2013 06:18:22 GMT

Replying to anonymous:

Isn't stdint.h protected for multiple inclusions?

Maybe!

In C99 it defines different things depending on whether __STDC_LIMIT_MACROS is defined or not, so rather like assert.h with NDEBUG it should really "correct itself" each time it's included depending upon the value of the macro. Thankfully C++11 does the sane thing and just requires that the limit macros are always defined.

Thanks for the explanation, I didn't know about this requirement.

Either way, we should really try to get the system defined limits macros if we can, just because we can't be certain of getting them every time, isn't a reason not to try.

Agreed.

status changed; resolution set

John Maddock — Sun, 24 Feb 2013 19:08:04 GMT

status new → closed
resolution → fixed

(In [83139]) Merge changes from Trunk. Fixes #6013. Fixes #7151. Fixes #7359. Fixes #7389. Fixes #7452. Fixes #7528. Fixes #7703. Fixes #7841. Fixes #7898. Fixes #7938. Fixes #8048.