Re: invalid arguments to public API: g_assert, g_return_if_fail or continue with undefined behavior

[Kalle Vahlman <kalle vahlman gmail com>]

2005/9/13, Christian Neumair <chris gnome-de org>:
> I've noted significant inconsistencies wrt the handling of invalid
> arguments to functions. While GTK+ seems to take care of notifying the
> API client about failures by having various g_return_if_fail statements
> in front of virtually every public API, the EvolutionDataServer
> according to Sven Herzberg has asserts in the very beginning of many
> public API codeblocks. GnomeVFS instead often seems to not check for
> this at all, resulting in NULL strcmps etc.. Just check out
> gnome-vfs-mime-handlers.c and you get the gist.
> 
> I'd really like to have a GNOME-wide policy for dealing with public API
> and invalid arguments. If we feel like the traditional C route is good,
> we can remove all of these codeblocks for the sake of performance. I
> think some of the asserts/return_if_fail statements were left out for
> exactly that reason. I suppose this has a measurable performance impact
> for little helpers that are often called.
> 
> On the other hand, programmers using our API will probably kill us if we
> remove them. So maybe we've got to make a decision whether we should
> enforce the usage of g_assert or g_return_if_fail.

I think there is no reason to leave them out as:

http://cvs.gnome.org/viewcvs/glib/glib/gmessages.h?view=markup
---8<-----

#ifdef G_DISABLE_CHECKS

#define g_return_if_fail(expr)			G_STMT_START{ (void)0; }G_STMT_END
#define g_return_val_if_fail(expr,val)		G_STMT_START{ (void)0; }G_STMT_END
#define g_return_if_reached()			G_STMT_START{ return; }G_STMT_END
#define g_return_val_if_reached(val)		G_STMT_START{ return (val); }G_STMT_END

#else /* !G_DISABLE_CHECKS */

---8>----

So probably gnome-vfs (and any other app not doing those) should be "fixed".

-- 
Kalle Vahlman, zuh iki fi