Re: c question

[Tom Gilbert <gilbertt tomgilbert freeserve co uk>]

* Chris Jones (chris@black-sun.co.uk) wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> Hi
> 
> > void function(char *string="default");
> > 
> > and be able to call it with
> > 
> > function();
> 
> Why not just do:
> 
> void function( char *string )
> {
> 	if( string == NULL ) {
> 		string = strdup( "default" );
> 	}
> 
> 	/* ... */
> 
> 	free( string );
        ^^^^^^^^^^^^^^^ 

Its a good idea not to try to free a constant string literal ;-)

> 
> }
> 
> int main()
> {
> 	function( "moo" );
        ^^^^^^^^^^^^^^^^^^
This line will segfault, as the function tries to free "moo", which
was never malloc'ed.

> 	function( NULL );
> }
> 
> it does mean that you can't just call "function();" - you have to put
> a NULL as the argument, but it works just fine.


This is the right solution though :)

I like:

 void function( char *string )
 {
     int def=FALSE;
     
 	if( string == NULL ) {
 		string = strdup( "default" );
		def=TRUE;
 	}
 
 	/* ... */
 
     if(def)
 	free( string );
 }

int main()
 {
       function( "moo" );
       function( NULL );
 }

But I'm just splitting hairs now.

Tom.
-- 
            .-------------------------------------------------------.
    .^.     | Tom Gilbert, England | tom@tomgilbert.freeserve.co.uk |
    /V\     |----------------------| www.tomgilbert.freeserve.co.uk |
   // \\    | Sites I recommend:   `--------------------------------|
  /(   )\   | www.freshmeat.net www.enlightenment.org www.gnome.org |
   ^^-^^    `-------------------------------------------------------'