standards/60772: _Bool and bool should be unsigned
jasone at canonware.com
Thu Jan 1 11:26:40 PST 2004
On Thu, Jan 01, 2004 at 03:52:08PM +1100, Bruce Evans wrote:
> The fake definition in FreeBSD-4.9 permits storing values between INT_MIN
> and INT_MAX, and changing it to unsigned so that it is limited to values
> between 0 and UINT_MAX isn't much of an improvment.
You're talking about the following problem, right?
int foo = 42;
/* This works okay. */
bar = foo ? true : false;
/* This breaks on 4.9. */
bar = foo;
This particular problem hasn't bitten me, but you're right that it's a
> I think the correct fix is to remove <stdbool.h> in RELENG_4, since it is
> impossible to implement it correctly.
This sounds reasonable to me, though doing so would potentially prevent
quite a number of ports from compiling. Still, it seems better to refuse
to compile, than to willingly generate bad binaries. This bug caused a
spectacular failure for some code I've been working on, but the resulting
bugs could easily have been much more subtle and gone unnoticed.
> Was there a defacto standard for it before C99? It doesn't seem to have
> been very common -- it isn't in glibc-2.2.5 (which is 2 years old, but
> not as old as <stdnool.h> in FreeBSD).
I don't don't think there was a defacto standard for this. The following
appears to be the original C99 addition document for stdbool.h:
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