Behaviour of setjmp/longjmp and registers

[David Haynes]

What should be the result of running the following program?

#include <setjmp.h>

main()
{
	register int j;
	jmp_buf env;

	j = 1;
	if(setjmp(env) == 1) {
		printf("j = %d\n", j);
		exit(1);
	}
	printf("j = %d\n", j);
	j += 3;
	longjmp(env, 1);
}

Sequent, Ultrix and Vax C give results of j = 1, j = 4.
Gcc gives a result of j = 1, j = 1.
What does the ANSI standard say about this?

-david-