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From: gwyn@smoke.brl.mil (Doug Gwyn)
Newsgroups: comp.lang.c
Subject: Re: Assignment Ops and Side Effects
Message-ID: <15777@smoke.brl.mil>
Date: 10 Apr 91 04:24:25 GMT
References: <18324@crdgw1.crd.ge.com> <15765@smoke.brl.mil> <18355@crdgw1.crd.ge.com>
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.
Lines: 20

In article <18355@crdgw1.crd.ge.com> volpe@camelback.crd.ge.com (Christopher R Volpe) writes:
>In article <15765@smoke.brl.mil>, gwyn@smoke.brl.mil (Doug Gwyn) writes:
>|>In article <18324@crdgw1.crd.ge.com> volpe@camelback.crd.ge.com (Christopher R Volpe) writes:
>|>>The result of "c=1" in an expression context should be promoted to int.
>|>Not if it's the operand of sizeof; that would make sizeof rather useless.
>I don't think it would be useless at all. I could still do sizeof(c) and
>get the size of a char if I wanted. Can you point me to a reference to
>the Standard from which one can deduce that a NON-lvalue expression
>of type char should NOT be promoted to int when it is the operand of
>sizeof?

Yeah -- the whole damn standard.  It doesn't contain a specific
statement that says "Don't invent rules along the lines of Volpe";
instead it gives rules for properly determining what does happen:
3.3.16 Semantics:  The type of an assignment expression is the type of
the left operand...
3.3.3.4 Semantics:  The sizeof operator ... size is determined from
the type of the operand, which is not itself evaluated.
I see no room for for thinking that any sort of conversion should be
performed.