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From: gwyn@smoke.brl.mil (Doug Gwyn)
Newsgroups: comp.lang.c
Subject: Re: sizeof() confusion
Message-ID: <14501@smoke.brl.mil>
Date: 17 Nov 90 13:52:12 GMT
References: <1990Nov14.154213.27324@cbnewsj.att.com> <14462@smoke.brl.mil> <1990Nov16.141352.22426@dce.ie>
Organization: U.S. Army Ballistic Research Laboratory, APG, MD.
Lines: 20

In article <1990Nov16.141352.22426@dce.ie> ch@dce.ie (Charles Bryant) writes:
>> there are two distinct uses of sizeof:
>>	sizeof unary_expression
>>	sizeof ( type_name )
>That must make parsing it more difficult than if the parentheses were always
>required ...

Yes, but this is necessary since C has "always" (actually, just for a long
time) had those two distinct usages of "sizeof".

Note that most published precedence tables for C operators, including K&R's,
get this wrong.  Using an example similar to the one you gave:

	sizeof ( short ) - 1
K&R's chart (p. 49 or 53, depending on edition) would have one parse this as
	sizeof ((short) (- 1))
whereas the only valid parse according to the C standard (and all existing
compilers of which I am aware) is
	(sizeof (short)) - 1
which has a different value.