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From: mcdaniel@uicsrd.csrd.uiuc.edu
Newsgroups: comp.std.c
Subject: Re: A Little Quibble
Message-ID: <25200002@uicsrd.csrd.uiuc.edu>
Date: 8 Dec 88 23:01:00 GMT
References: <25200001@uicsrd.csrd.uiuc.edu>
Lines: 46
Nf-ID: #R:uicsrd.csrd.uiuc.edu:25200001:uicsrd.csrd.uiuc.edu:25200002:000:1196
Nf-From: uicsrd.csrd.uiuc.edu!mcdaniel    Dec  8 17:01:00 1988


Please excuse more of my quibbling . . .

Is the program below legal under dpANS?   Is it guaranteed to output 1?

#include <stdio.h>
int a = 1;
main()
    {
    int a = 2; /* Y */
        {
        extern int a; /* Z */
        printf("%d\n", a);
        }
    }

On the VAX BSD 4.3 compiler, it complaints about line Z (redeclaration
of a).  If line Y is changed to "extern int a;", though, it compiles
fine.

What if I change line Z to "extern const int a;"?


About my base note's program (here reprinted)
    #include <stdio.h>
    main() {
	int a; a = 1;
	{ int a = a; printf("a=%d\n", a); }
	exit(0);
	}

The BSD 4.3 compiler apparently evaluates the right-hand side of
	int a = a;
in the context of the current block (as if it were
	int a; a = a;
); this program does not output "1".

--

             Tim, the Bizarre and Oddly-Dressed Enchanter

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