Messages in this thread |  | | Subject | Re: [PATCH] compiler.h: fix error in BUILD_BUG_ON() reporting | From | Vegard Nossum <> | Date | Tue, 31 Mar 2020 21:08:42 +0200 |
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On 3/31/20 9:00 PM, Joe Perches wrote: > On Tue, 2020-03-31 at 20:56 +0200, Rasmus Villemoes wrote: >> On 31/03/2020 20.20, Joe Perches wrote: >>> On Tue, 2020-03-31 at 13:26 +0200, Vegard Nossum wrote: >>>> #define compiletime_assert(condition, msg) \ >>>> - _compiletime_assert(condition, msg, __compiletime_assert_, __LINE__) >>>> + _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__) >>> >>> This might be better using something like __LINE__ ## _ ## __COUNTER__ >>> >>> as line # is somewhat useful to identify the specific assert in a file. >>> >> >> Eh, if the assert fires, doesn't the compiler's diagnostics already >> contain all kinds of location information? > > I presume if that were enough, > neither __LINE__ nor __COUNTER__ > would be useful. >
__LINE__ is only used currently for creating a unique identifier, as far as I can tell.
The way it works is that it creates a function declaration with the attribute __attribute__((error(message))), which makes gcc throw an error if the function is ever used (i.e. calls are not compiled out).
The number does appear in the output, but it's not even really obvious that it's a line number. And the compiler's diagnostics are pretty good at showing the whole "stack trace" of where the call came from (including the proper line numbers).
Vegard
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