Re: [GnomeMeeting-list] 64bit patch

[Miguel Rodríguez <migrax terra es>]

Ummm. It's true that NULL is c++ is defined as 0 (Stroustrup in his book
even mentions that NULL shouldn't be used, and that you should use just
0).
But, doesn't gcc just automatically promote that 0 to 64 bits, as it's
really a pointer?

El mi�09-10-2002 a las 11:37, Alexander Larsson escribi� I'd like this patch to be applied:
> 
> Index: src/main_window.cpp
> ===================================================================
> RCS file: /cvs/gnome/gnomemeeting/src/main_window.cpp,v
> retrieving revision 1.117
> diff -u -p -r1.117 main_window.cpp
> --- src/main_window.cpp	6 Oct 2002 21:41:34 -0000	1.117
> +++ src/main_window.cpp	9 Oct 2002 09:26:15 -0000
> @@ -911,7 +911,7 @@ gnomemeeting_init (GmWindow *gw, 
>  		      GNOME_PARAM_HUMAN_READABLE_NAME,
>  		      _("GnomeMeeting"),
>  		      GNOME_PARAM_APP_DATADIR, DATADIR,
> -		      NULL);
> +		      (void *)NULL);
>  
>    gm = gnome_app_new ("gnomemeeting", _("GnomeMeeting"));
>  
> 
> It fixes a bug on 64bit systems.
> 
> Scary details:
> 
> On 64bit systems int is 32bit and pointers are 64bit, and in C++ NULL is 
> defined as 0, not (void *)0 as is common in C[1]. When passing NULL 
> through a varargs list (such as above) in C++ the compiler can't know from 
> the context wether the 0 is a pointer or an int, so it picks int. On 64bit 
> systems this means some random 32 bits of data is used for the other half 
> of the pointer in the called function.
> 
> [1] The language lawyers among us will probably tell me that C doesn't 
> guarantee NULL to be (void *)0 either. This is true, but most C 
> implementations use it, and lots of other gtk+/gnome code would break if 
> this wasn't the  case.
> 
> -- 
> =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
>  Alexander Larsson                                            Red Hat, Inc 
>                    alexl redhat com    alla lysator liu se 
> He's a gun-slinging shark-wrestling stage actor on the edge. She's a 
> warm-hearted nymphomaniac bodyguard from the wrong side of the tracks. They 
> fight crime! 
> 
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