Path: utzoo!utgpu!water!watmath!clyde!att!whuts!homxb!genesis!hotlr!anumb!eao
From: eao@anumb.UUCP (e.a.olson)
Newsgroups: comp.std.c
Subject: Re: switch (expression)
Message-ID: <287@anumb.UUCP>
Date: 14 Jul 88 16:21:00 GMT
References: <1988Jul12.105547.13268@light.uucp> <755@vsi.UUCP>
Reply-To: eao@anumb.UUCP (e.a.olson)
Organization: AT&T Bell Laboratories - MV
Lines: 20

In article <755@vsi.UUCP> sullivan@vsi.UUCP (Michael T Sullivan) writes:
>In article <1988Jul12.105547.13268@light.uucp>, bvs@light.uucp (Bakul Shah) writes:
>I don't know about casting should be avoided.  I'm looking at shmop(2) manual
>page for our 3B2 (shared memory operation) and it says:
...
>	Otherwise, a value of -1 is returned and errno is set to indicate
>	the error."
>
>Somebody at AT&T must think casting a pointer to an int (or a long) isn't
>such a bad idea, unless I'm missing something (it has been known to happen).

    I think that this might be due more to the convention that all
    section 2 calls return a -1 for error (and the fact that
    shmop feels that zero is fine to return) than to anything to
    do with how AT&T feels about casting a pointer to an int.

    In any case, as long as the system call and the caller share the
    same machine, and both the system call and the caller cast from
    a pointer to an int (or a long), then whatever -1 happens to be,
    both will agree on its value.