I have the following function from some legacy code that I am maintaining.

long getMaxStart(long start, long count, const myStruct *s1, ...)
{
   long     i1, maxstart;
   myStruct *s2;
   va_list  marker;

   maxstart = start;

   /*BUGFIX: 003 */
   /*(va_start(marker, count);*/
   va_start(marker, s1);

   for (i1 = 1; i1 <= count; i1++)
   {
      s2 = va_arg(marker, myStruct *);           /* <- s2 is assigned null here */
      maxstart = MAX(maxstart, s2->firstvalid);  /* <- SEGV here */
   }

   va_end(marker);
   return (maxstart);
}

When the function is called with only one myStruct argument, it causes a SEGV. The code compiled and run without crashing on Windows XP when I compiled it using VS2005. I have now moved the code to Ubuntu Karmic and I am having problems with the stricter compiler on Linux. Is anyone able to spot what is causing the parameter not to be read correctly in the var_arg() statement?

I am compiling using gcc version 4.4.1

Edit

The statement that causes the SEGV is this one:

start = getMaxStart(start, 1, ms1);

The variables 'start' and 'ms1' have valid values when the code execution first reaches this line.