Re: How to prototype functions that return pointers

[Steve Graegert <graegerts@gmail.com>]

On 6/24/05, James Colannino <james@colannino.org> wrote:
> Ok, so this is a very embarassing question.  I tried googling for the
> answer but haven't figured it out yet, and everything I've tried results
> in compilation errors. I want to prototype a function that takes nothing
> as an argument but returns a pointer to a character.
> 
> I've tried the following:
> 
> char * readline();
> char *readline();

I can't see a problem with this declaration, thus I am not able to
reproduce the error(s).  What I see here is a function taking an
arbitrary number of arguments returning a pointer to a char.

> These first two result in 4 errors, each one identical and each one
> telling me "error: two or more data types in declaration of 'readline' "
> 
> *char readline();
> * char readline();

This is obviously wrong because you're trying to dereference a data
type, not an identifier. Everything else that follows in this line is
discarded by the parser.

I have compiled three different function declarations that all have a
different meaning to help you understand what could have been wrong:

/* pointer to func() returning a char */
char (*func)();

/* function taking a char pointer and returning char-pointer */
char* f(char *);

/* 
 * pointer to a function taking pointer to a char,
 * returning a pointer to a char
 */
char* (*fp)(char *);

Hope this clarifies the relations between pointers and functions and
their arguments.


Kind Regards

    \Steve

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Steve Graegert <graegerts@gmail.com> || <http://www.technologies.de/~sg/>
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