Bug iwith setjmp/longjmp on Vax

[Chris Torek]

Your code has a nasty little no-no in it: it longjmp's after the stack
environment in which the setjmp was done has been deallocated.  No
surprise it fails ``at random''.  Watch:

--------#include <setjmp.h>
--------static jmp_buf env;
--------int mode;
--------main() {
active: env=uninit, mode=0, main()
--------	foo();
[expand foo()]
[]------foo() {
active: env=uninit, mode=0, main(), foo()
[]------	mode = setjmp(env);
active: env=foo(), mode=0, main(), foo()
[]------	if (mode != 0) magic();
[]------}
[return to main()]
active: env=foo() [defunct], mode=0, main()
--------	longjmp(env, 1);

Oops.
-- 
In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 454 4251)
UUCP:	seismo!umcp-cs!chris
CSNet:	chris at umcp-cs		ARPA:	chris at maryland