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From: volpe@camelback.crd.ge.com (Christopher R Volpe)
Newsgroups: comp.std.c
Subject: Re: struct* mention before declaration/definition
Message-ID: <20802@crdgw1.crd.ge.com>
Date: 21 Jun 91 18:53:04 GMT
References: <142762@unix.cis.pitt.edu>
Sender: news@crdgw1.crd.ge.com
Reply-To: volpe@camelback.crd.ge.com (Christopher R Volpe)
Lines: 43

In article <142762@unix.cis.pitt.edu>, msw@unix.cis.pitt.edu (Matt S
Wartell) writes:
|>	/* declaration of function */
|>	void add_version(int a, struct B *b);
                                ^^^^^^^^ Implicit declaration of incomplete
                                         type whose scope is the
prototype itself.
                                         You don't want this.

|>
|>	/* definition of structure */
|>	struct B {
|>		...
|>	};
        Declaration of new type not yet seen at this scope. This is fine.
 
|>
|>	/* definition of function */
|>	void add_version(int a, struct B *b)
                                ^^^^^^^^
                                Reference to type already declared in outer
                                scope above. This type is a DIFFERENT TYPE
                                from the one that appears in the prototype
                                declaration.
|>	{
|>		...
|>	}
|>
|>When the compiler gets to the function definition, it complains of a type
|>mismatch in parameter b.  It is our impression that the compiler should
|>produce an error at the function _declaration_ because the declaration
|>uses an undefined, undeclared type.
|>-- 
|>matt wartell, university of pittsburgh             msw@unix.cis.pitt.edu

The compiler is correct. Move the declaration of struct B before the
prototype.

-Chris                                
==================
Chris Volpe
G.E. Corporate R&D
volpecr@crd.ge.com