This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
The _longjmp() and _setjmp() functions shall be equivalent to
longjmp() and setjmp(), respectively, with the additional restriction
that _longjmp() and _setjmp() shall not manipulate the signal mask.
If _longjmp() is called even though env was never initialized by a
call to _setjmp(), or when the last such call was in a function that
has since returned, the results are undefined.
If _longjmp() is executed and the environment in which _setjmp() was
executed no longer exists, errors can occur. The conditions under
which the environment of the _setjmp() no longer exists include
exiting the function that contains the _setjmp() call, and exiting an
inner block with temporary storage. This condition might not be
detectable, in which case the _longjmp() occurs and, if the
environment no longer exists, the contents of the temporary storage
of an inner block are unpredictable. This condition might also cause
unexpected process termination. If the function has returned, the
results are undefined.
Passing longjmp() a pointer to a buffer not created by setjmp(),
passing _longjmp() a pointer to a buffer not created by _setjmp(),
passing siglongjmp() a pointer to a buffer not created by
sigsetjmp(), or passing any of these three functions a buffer that
has been modified by the user can cause all the problems listed
above, and more.
The _longjmp() and _setjmp() functions are included to support
programs written to historical system interfaces. New applications
should use siglongjmp() and sigsetjmp() respectively.
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) In the event of any discrepancy between this version and
the original IEEE and The Open Group Standard, the original IEEE and
The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.unix.org/online.html .
Any typographical or formatting errors that appear in this page are
most likely to have been introduced during the conversion of the
source files to man page format. To report such errors, see
IEEE/The Open Group 2013 _LONGJMP(3P)