Originální popis anglicky:
longjmp - non-local goto
Návod, kniha: POSIX Programmer's Manual
#include <setjmp.h>
void longjmp(jmp_buf
env, int
val );
The
longjmp() function shall restore the environment saved by the most
recent invocation of
setjmp() in the same thread, with the
corresponding
jmp_buf argument. 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() ,
sigaction() ,
siglongjmp() ,
sigsetjmp()
, the Base Definitions volume of IEEE Std 1003.1-2001,
<setjmp.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. 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.opengroup.org/unix/online.html
.
