[pulseaudio-discuss] bools and bit-fields
remi at remlab.net
Thu Aug 18 08:09:36 PDT 2011
Le jeudi 18 août 2011 17:53:43 Arun Raghavan, vous avez écrit :
> The condition in the if statement may evaluate to false if pa_bool_t is
> typedef'ed to a signed type (it definitely is if you don't have
> stdbool.h, not sure if _Bool is a signed type or not).
The ISO C standard requires that _Bool bit fields with non-zero width can
store _and_ *compare* to 0 and 1.
> This happens
> because it's a single bit field and thus when the msb (the only bit) is
> set to 1 it is interpreted as -1.
Right. So pa_bool_t should be typedef'd to 'unsigned' rather than 'int'
wherever HAVE_STD_BOOL is not defined.
Then again, <stdbool.h> is a non-optional part of the C standard. Defining
your own boolean type feels very 90's (and indeed error-prone).
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