Re: [HACKERS] taking stdbool.h into use

Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> Michael Paquier wrote:
>> It seems to me that this proves the point of the proposed patch. You
>> had better use a zero-equality comparison for such bitwise operation,
>> and so you ought to do that:
>> bool        isprimary = (flags & INDEX_CREATE_IS_PRIMARY) != 0;

> Right, exactly.  But my point is that with the whole patch series
> applied I didn't get any warnings.

While warnings for this would be lovely, I don't see how we can expect to
get any.  This is perfectly correct C code no matter whether isprimary
is C99 bool or is typedef'd to char ... you just end up with different
values of isprimary, should the RHS produce something other than 1/0.
The compiler has no way to know that assigning, say, 4 in the char
variable case is not quite your intent.  Maybe you could hope for a
warning if the bit value were far enough left to actually not fit into
"char", but otherwise there's nothing wrong.
        regards, tom lane


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