Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!apple!bloom-beacon!bu-cs!buengc!bph
From: bph@buengc.BU.EDU (Blair P. Houghton)
Newsgroups: comp.lang.c++
Subject: Re: Isn't sizeof an operator?
Message-ID: <2430@buengc.BU.EDU>
Date: 30 Mar 89 18:03:21 GMT
References: <8903281246.AA26233@wheat-chex.ai.mit.edu>
Reply-To: bph@buengc.bu.edu (Blair P. Houghton)
Followup-To: comp.lang.c++
Organization: Boston Univ. Col. of Eng.
Lines: 32

In article <8903281246.AA26233@wheat-chex.ai.mit.edu> hearn@claris.com writes:
>In article <8903202240.AA24954@yahi> tiemann@lurch.stanford.edu writes:
>>[...And I wrote...but someone lopped off the attribution...]
>>>In article <123@riunite.ACA.MCC.COM> rfg@riunite.UUCP (Ron Guilmette) writes:
>>>>   	["why isn't sizeof declarable as an operator?"]
>>>
>>>     Because it's a compiler directive, not a C-language operator.  The
>>>     result of sizeof (something) is an integer _constant_.  If you try to
>>>     take the size of something that has a varying size, you will get only
>>>     the size of that thing at compile time.
>>>
>>>     If you're creating varying-sized data elements, you should keep track of
>>>     their sizes yourself.
>>
>>     It also takes a TYPE as an argument instead of an EXPRESSION.
>
>You are 100% incorrect.  Remember that the topic of discussion here is
>C++, not C!  sizeof is certainly an operator.  And it can take a type
>or an expression as an argument.  See Stroustrup, pp. 257-258.  It is,
>however, resolved at compile time.

Hurh?  If it's resolved at compile time, how can it be an operator that
returns the value of a varying quantity?  Oh.  I get it.  I mean "it's not
a FUNCTION, it's a compiler-directing operator..."  Sorry.  I zegged when
I shoulda zogged.  Not enuff wheat-chex for breakfast.

[...discussion of non-overloadability of sizeof deleted...]
>Unfortunately, for now, there seems to be no alternative but to keep track
>of the sizes yourself.  Not very helpful, I know, but at least correct. :-)

				--Blair
				  "Deja vu."