1_LONGJMP(P)                POSIX Programmer's Manual               _LONGJMP(P)
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NAME

6       _longjmp, _setjmp - non-local goto
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SYNOPSIS

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

16       The _longjmp() and _setjmp() functions shall be equivalent to longjmp()
17       and  setjmp(),  respectively,  with  the  additional  restriction  that
18       _longjmp() and _setjmp() shall not manipulate the signal mask.
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20       If _longjmp() is called even though env was never initialized by a call
21       to _setjmp(), or when the last such call was in  a  function  that  has
22       since returned, the results are undefined.
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RETURN VALUE

25       Refer to longjmp() and setjmp() .
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ERRORS

28       No errors are defined.
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30       The following sections are informative.
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EXAMPLES

33       None.
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APPLICATION USAGE

36       If  _longjmp()  is  executed and the environment in which _setjmp() was
37       executed no longer exists, errors  can  occur.   The  conditions  under
38       which the environment of the _setjmp() no longer exists include exiting
39       the function that contains the _setjmp() call,  and  exiting  an  inner
40       block  with temporary storage.  This condition might not be detectable,
41       in which case the _longjmp() occurs and, if the environment  no  longer
42       exists,  the  contents  of  the temporary storage of an inner block are
43       unpredictable. This condition might also cause unexpected process  ter‐
44       mination. If the function has returned, the results are undefined.
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46       Passing  longjmp() a pointer to a buffer not created by setjmp(), pass‐
47       ing _longjmp() a pointer to a buffer not created by _setjmp(),  passing
48       siglongjmp() a pointer to a buffer not created by sigsetjmp(), or pass‐
49       ing any of these three functions a buffer that has been modified by the
50       user can cause all the problems listed above, and more.
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52       The _longjmp() and _setjmp() functions are included to support programs
53       written to historical system interfaces.  New applications  should  use
54       siglongjmp() and sigsetjmp() respectively.
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RATIONALE

57       None.
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FUTURE DIRECTIONS

60       The _longjmp() and _setjmp() functions may be marked LEGACY in a future
61       version.
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SEE ALSO

64       longjmp() , setjmp() , siglongjmp() , sigsetjmp() ,  the  Base  Defini‐
65       tions volume of IEEE Std 1003.1-2001, <setjmp.h>
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68       Portions  of  this text are reprinted and reproduced in electronic form
69       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
70       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
71       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
72       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
73       event of any discrepancy between this version and the original IEEE and
74       The  Open Group Standard, the original IEEE and The Open Group Standard
75       is the referee document. The original Standard can be  obtained  online
76       at http://www.opengroup.org/unix/online.html .
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80IEEE/The Open Group                  2003                          _LONGJMP(P)
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