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From: eppstein@garfield.columbia.edu (David Eppstein)
Newsgroups: net.lang.c++
Subject: C++ and sizeof
Message-ID: <3522@columbia.UUCP>
Date: Fri, 17-Oct-86 13:14:07 EDT
Article-I.D.: columbia.3522
Posted: Fri Oct 17 13:14:07 1986
Date-Received: Fri, 17-Oct-86 22:57:25 EDT
Sender: nobody@columbia.UUCP
Organization: Columbia University CS Department
Lines: 18

Is there a good reason why CC expands sizeof itself?  E.g. in

test.c:				test..c:
    struct x {			    struct x { /* sizeof = 8 */
	int a;			    int _x_a ;
	float b;		    float _x_b ;
    };				    } ;

    int foo(struct x y)		    int foo (_auto_y )struct x _auto_y ;
    {				    {
	return y.a + sizeof(y);	    return (_auto_y . _x_a + 8);
    }				    }

why does the  sizeof(y)  become  8  and not  sizeof(struct x)?
Is there some other use CC makes of the size that makes up for the
resulting lack of portability?
-- 
David Eppstein, eppstein@cs.columbia.edu, seismo!columbia!cs!eppstein