daniel@osf.org (Daniel Dardailler) (07/19/90)
I have a g++ problem:
main()
{
int (* foo) ();
}
doesn't compile with: `foo' undeclared (first use this function)
but:
main()
{
static int (* foo) ();
}
and
int (* foo) ();
main()
{
}
works fine.
Any idea?
Daniel Dardailler | OSF/Motif Team
Open Software Foundation | Email : daniel@osf.org
11 Cambridge Center | Phone : (617) 621 8840
CAMBRIDGE, MA 02142 | Fax : (617) 621 0584krohn@czech.sw.mcc.com (Eric Krohn) (07/20/90)
In article <10983@paperboy.OSF.ORG> daniel@osf.org (Daniel Dardailler) writes:
] I have a g++ problem:
]
] main()
] {
] int (* foo) ();
] }
] doesn't compile with: `foo' undeclared (first use this function)
Welcome to one of the C++ language's inherent ambiguities. A statement of
the form
T (* foo) ();
(where T is a typename) could be either:
1) an expression // Dereference foo, cast it to a T, call function or
// overloaded operator ().
2) a declaration // foo is pointer to function returning T.
As of AT&T's C++ 2.0, the language manual says if a statement can be parsed as
either an expression or a declaration, then it must be parsed as a declaration.
In your case, g++ parsed it (incorrectly) as an expression.
When you added the storage class specifier (static), you disambiguated the
statement so that it could only be parsed as a declaration.
If you want to force your statement to be parsed as an expression, you can say
0, int (*foo) ();
--
Eric J. Krohn
krohn@sw.mcc.com