1LONGJMP(3)                     Library functions                    LONGJMP(3)
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NAME

6       longjmp, siglongjmp - non-local jump to a saved stack context
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SYNOPSIS

9       #include <setjmp.h>
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11       void longjmp(jmp_buf env, int val);
12       void siglongjmp(sigjmp_buf env, int val);
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DESCRIPTION

15       longjmp()  and  setjmp()  are useful for dealing with errors and inter‐
16       rupts encountered in a low-level subroutine of  a  program.   longjmp()
17       restores  the  environment  saved by the last call of setjmp() with the
18       corresponding env argument.  After longjmp() is completed, program exe‐
19       cution  continues  as  if  the  corresponding call of setjmp() had just
20       returned the value val.  longjmp() cannot cause 0 to be  returned.   If
21       longjmp  is  invoked  with  a  second argument of 0, 1 will be returned
22       instead.
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24       siglongjmp() is similar to longjmp() except for the  type  of  its  env
25       argument.   If  the  sigsetjmp() call that set this env used a non-zero
26       savesigs flag, siglongjmp() also restores the set of blocked signals.
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RETURN VALUE

29       These functions never return.
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CONFORMING TO

32       C89, C99, and POSIX.1-2001 specify longjmp().   POSIX.1-2001  specifies
33       siglongjmp().
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NOTES

36       POSIX  does  not specify whether longjmp() will restore the signal con‐
37       text.  If you want to save and restore signal masks, use siglongjmp().
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39       longjmp() and siglongjmp() make programs hard to understand  and  main‐
40       tain.  If possible an alternative should be used.
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SEE ALSO

43       setjmp(3), sigsetjmp(3)
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47                                  1997-03-02                        LONGJMP(3)