sprintf container

From: vertigo (none_at_microsoft.com)
Date: 08/27/04 

Date: Fri, 27 Aug 2004 11:48:53 +0200

Hello
I want to write function which will return me string
formatted by sprintf:

char* sprintf_container(const char *format,...){
        str=malloc('what size' ??);
        sprintf(str,format,???);
        return str;
}

But how should i pass other parameters to sprintf ?

Thanx
Michal