Why have xxx_t typedef names (was Re: Is typedef char BUFFER[20] legal?)

[Doug Gwyn]

In article <23134 at netcom.COM> avery at netcom.COM (Avery Colter) writes:
>It might be, since these seem to be so widespread, that the standards
>committee might have sanctioned certain of these xxx_t types as being
>standard parameter or return types of some of the standard library
>functions.

Yes, the C standard does that.  However, the types are associated
with relevant standard headers rather than a separate <sys/types.h>.