1_LONGJMP(3P)               POSIX Programmer's Manual              _LONGJMP(3P)
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PROLOG

6       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
7       implementation of this interface may differ (consult the  corresponding
8       Linux  manual page for details of Linux behavior), or the interface may
9       not be implemented on Linux.
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NAME

12       _longjmp, _setjmp — non-local goto
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SYNOPSIS

15       #include <setjmp.h>
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17       void _longjmp(jmp_buf env, int val);
18       int _setjmp(jmp_buf env);
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DESCRIPTION

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

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

33       No errors are defined.
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35       The following sections are informative.
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EXAMPLES

38       None.
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APPLICATION USAGE

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

62       None.
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FUTURE DIRECTIONS

65       The _longjmp() and _setjmp() functions may be removed in a future  ver‐
66       sion.
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SEE ALSO

69       longjmp(), setjmp(), siglongjmp(), sigsetjmp()
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71       The Base Definitions volume of POSIX.1‐2017, <setjmp.h>
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74       Portions  of  this text are reprinted and reproduced in electronic form
75       from IEEE Std 1003.1-2017, Standard for Information Technology --  Por‐
76       table  Operating System Interface (POSIX), The Open Group Base Specifi‐
77       cations Issue 7, 2018 Edition, Copyright (C) 2018 by the  Institute  of
78       Electrical  and  Electronics Engineers, Inc and The Open Group.  In the
79       event of any discrepancy between this version and the original IEEE and
80       The  Open Group Standard, the original IEEE and The Open Group Standard
81       is the referee document. The original Standard can be  obtained  online
82       at http://www.opengroup.org/unix/online.html .
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84       Any  typographical  or  formatting  errors that appear in this page are
85       most likely to have been introduced during the conversion of the source
86       files  to  man page format. To report such errors, see https://www.ker‐
87       nel.org/doc/man-pages/reporting_bugs.html .
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91IEEE/The Open Group                  2017                         _LONGJMP(3P)
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