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LONGJMP(3P) POSIX Programmer's Manual LONGJMP(3P)
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.
longjmp — non-local goto
#include <setjmp.h>
void longjmp(jmp_buf env, int val);
The functionality described on this reference page is aligned with
the ISO C standard. Any conflict between the requirements described
here and the ISO C standard is unintentional. This volume of
POSIX.1‐2008 defers to the ISO C standard.
The longjmp() function shall restore the environment saved by the
most recent invocation of setjmp() in the same process, with the
corresponding jmp_buf argument. If the most recent invocation of
setjmp() with the corresponding jmp_buf occurred in another thread,
or if there is no such invocation, or if the function containing the
invocation of setjmp() has terminated execution in the interim, or if
the invocation of setjmp() was within the scope of an identifier with
variably modified type and execution has left that scope in the
interim, the behavior is undefined. It is unspecified whether
longjmp() restores the signal mask, leaves the signal mask unchanged,
or restores it to its value at the time setjmp() was called.
All accessible objects have values, and all other components of the
abstract machine have state (for example, floating-point status flags
and open files), as of the time longjmp() was called, except that the
values of objects of automatic storage duration are unspecified if
they meet all the following conditions:
* They are local to the function containing the corresponding
setjmp() invocation.
* They do not have volatile-qualified type.
* They are changed between the setjmp() invocation and longjmp()
call.
As it bypasses the usual function call and return mechanisms,
longjmp() shall execute correctly in contexts of interrupts, signals,
and any of their associated functions. However, if longjmp() is
invoked from a nested signal handler (that is, from a function
invoked as a result of a signal raised during the handling of another
signal), the behavior is undefined.
The effect of a call to longjmp() where initialization of the jmp_buf
structure was not performed in the calling thread is undefined.
After longjmp() is completed, program execution continues as if the
corresponding invocation of setjmp() had just returned the value
specified by val. The longjmp() function shall not cause setjmp() to
return 0; if val is 0, setjmp() shall return 1.
No errors are defined.
The following sections are informative.
None.
Applications whose behavior depends on the value of the signal mask
should not use longjmp() and setjmp(), since their effect on the
signal mask is unspecified, but should instead use the siglongjmp()
and sigsetjmp() functions (which can save and restore the signal mask
under application control).
None.
None.
setjmp(3p), sigaction(3p), siglongjmp(3p), sigsetjmp(3p)
The Base Definitions volume of POSIX.1‐2008, setjmp.h(0p)
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
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2013 LONGJMP(3P)
Pages that refer to this page: setjmp.h(0p), exit(3p), ftw(3p), _longjmp(3p), setjmp(3p), sigaction(3p), siglongjmp(3p)