@node setjmp, misc
@findex setjmp
@subheading Syntax

@example
#include <setjmp.h>

int setjmp(jmp_buf j);
@end example

@subheading Description

This function stores the complete CPU state into @var{j}.  This
information is complete enough that @code{longjmp} (@pxref{longjmp}) can
return the program to that state.  It is also complete enough to
implement coroutines.

@subheading Return Value

This function will return zero if it is returning from its own call. 
If longjmp is used to restore the state, it will return whatever value
was passed to longjmp, except if zero is passed to longjmp it will
return one. 

@subheading Portability

@portability ansi, posix

@subheading Example

@example
jmp_buf j;
if (setjmp(j))
  return;
do_something();
longjmp(j, 1);
@end example