void foo(SV * sv)
{
	if(sv)
	{
		printf("%s\n", SvPV_nolen(sv));
	}
}

void bar(SV * sv)
{
	printf ("%i\n", SvPOK(sv));
}

Mytest2::foo('asdf'); # prints asdf

Mytest2::bar(1); # prints 0

Mytest2::foo(1); # Segmentation Fault