On 18 February 2013 13:02, Comeau At9Fans <comeauat9f...@gmail.com> wrote:
> seems to be doing is setting up allowing the call to compile and once that > is satisfied then the subsequent definition "has" to match it, as perhaps a > way to do type punning. No, the compiler is simply applying scope rules. Without that inner declaration explicitly overriding the outer declaration--whether static or extern is used-- it will not compile (eg, if you put "static void fn(Outer*);" or "extern void fn(Outer*);" and remove static from fn in the file scope). The behaviour is undefined in ANSI C if two declarations that refer to the same object or function do not have compatible types (normally, you're protected by another rule that you can't have incompatible declarations *in the same scope*). ANSI C does, however, forbid the inner static declaration (which surprised me) "The declaration of an identifier for a function that has block scope shall have no explicit storage-class specifier other than extern." (6.7.1)
