Bug 22936
| Summary: | /usr/include/stdbool.h defines _bool twice when included by gcc. | ||||||
|---|---|---|---|---|---|---|---|
| Product: | Base System | Reporter: | Donald.J.Maddox <Donald.J.Maddox> | ||||
| Component: | misc | Assignee: | Jeroen Ruigrok van der Werven <asmodai> | ||||
| Status: | Closed FIXED | ||||||
| Severity: | Affects Only Me | ||||||
| Priority: | Normal | ||||||
| Version: | 5.0-CURRENT | ||||||
| Hardware: | Any | ||||||
| OS: | Any | ||||||
| Attachments: |
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On Sat, 18 Nov 2000 Donald.J.Maddox@cae88-102-101.sc.rr.com wrote: > >Description: > The header file <stdbool.h> contains a defective > conditional that breaks several ports. Any code that includes > <stdbool.h> will break if compiled by gcc... Example: Much more is broken than that, at least according to a C99 draft (n869). 1) _Bool is a first class type (like int), so it can't be declared as a typedef (unless compiler magic supports such a declaration). 2) `true' and `false' are supposed to be usable in cpp expressions, so they can't be declared as enum values. 3) The definitions of `false' and `true' as themself don't work in K&R mode. This is not a serious bug, since K&R code shouldn't include <stdbool.h>. 4) Support for the Standard C (c99) _Bool is premature, since gcc doesn't support _Bool as a first class type. <stdbool.h> is essentially a compatibility hack for pre-c99 compilers. The current version seems to be based on the gcc version. Both versions will break when gcc actually supports _Bool. Here is a version compatible with the C99 draft and K&R: --- #define __bool_true_false_are_defined 1 #define false 0 #define true 1 #define bool _Bool #if __STDC_VERSION__ < 199901L typedef int _Bool; #endif --- Bruce Thanks. Are you going to commit your fix and close the PR?
On Sun, Nov 19, 2000 at 04:18:45AM +1100, Bruce Evans wrote:
> On Sat, 18 Nov 2000 Donald.J.Maddox@cae88-102-101.sc.rr.com wrote:
>
> > >Description:
> > The header file <stdbool.h> contains a defective
> > conditional that breaks several ports. Any code that includes
> > <stdbool.h> will break if compiled by gcc... Example:
>
> Much more is broken than that, at least according to a C99 draft (n869).
> 1) _Bool is a first class type (like int), so it can't be declared as
> a typedef (unless compiler magic supports such a declaration).
> 2) `true' and `false' are supposed to be usable in cpp expressions, so
> they can't be declared as enum values.
> 3) The definitions of `false' and `true' as themself don't work in K&R
> mode. This is not a serious bug, since K&R code shouldn't include
> <stdbool.h>.
> 4) Support for the Standard C (c99) _Bool is premature, since gcc doesn't
> support _Bool as a first class type.
>
> <stdbool.h> is essentially a compatibility hack for pre-c99 compilers.
> The current version seems to be based on the gcc version. Both versions
> will break when gcc actually supports _Bool.
>
> Here is a version compatible with the C99 draft and K&R:
>
> ---
> #define __bool_true_false_are_defined 1
> #define false 0
> #define true 1
>
> #define bool _Bool
> #if __STDC_VERSION__ < 199901L
> typedef int _Bool;
> #endif
> ---
>
> Bruce
>
On Sat, 18 Nov 2000, Donald J . Maddox wrote:
> Thanks. Are you going to commit your fix and close the PR?
I hope the committer of <stdbool.h> wll fix it. I didn't get around
to reviewing it before it was committed :(.
Bruce
Responsible Changed From-To: freebsd-bugs->asmodai Asmo brought it, so he'll fix it. State Changed From-To: open->suspended Committed a fix per bde's suggestions. Put on suspend until sobomax is happy. This PR is suspended 'until sobomax is happy'... Is he happy yet? :) State Changed From-To: suspended->closed I'm happy now, whatever it means!!! |
The header file <stdbool.h> contains a defective conditional that breaks several ports. Any code that includes <stdbool.h> will break if compiled by gcc... Example: #include <stdbool.h> int main() { return(0); } $ cc test.c In file included from test.c:1: /usr/include/stdbool.h:51: conflicting types for `_Bool' /usr/include/stdbool.h:38: previous declaration of `_Bool' How-To-Repeat: See above :)