longjmp(3) - phpMan

Command: man perldoc info search(apropos)  


LONGJMP(3)                 Linux Programmer's Manual                LONGJMP(3)



NAME
       longjmp, siglongjmp - non-local jump to a saved stack context

SYNOPSIS
       #include <setjmp.h>

       void longjmp(jmp_buf env, int val);

       void siglongjmp(sigjmp_buf env, int val);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       siglongjmp(): _POSIX_C_SOURCE >= 1 || _XOPEN_SOURCE || _POSIX_C_SOURCE

DESCRIPTION
       longjmp()  and  setjmp(3) are useful for dealing with errors and interrupts encoun-
       tered in a low-level subroutine of a program.  longjmp() restores  the  environment
       saved  by  the  last  call of setjmp(3) with the corresponding env argument.  After
       longjmp() is completed, program execution continues as if the corresponding call of
       setjmp(3)  had  just  returned  the  value  val.   longjmp()  cannot  cause 0 to be
       returned.  If longjmp() is invoked with a second argument of 0, 1 will be  returned
       instead.

       siglongjmp()  is similar to longjmp() except for the type of its env argument.  If,
       and only if, the sigsetjmp(3) call that set this env used a non-zero savesigs flag,
       siglongjmp() also restores the signal mask that was saved by sigsetjmp(3).

RETURN VALUE
       These functions never return.

CONFORMING TO
       C89, C99, and POSIX.1-2001 specify longjmp().  POSIX.1-2001 specifies siglongjmp().

NOTES
       POSIX does not specify whether longjmp()  will  restore  the  signal  context  (see
       setjmp(3)  for some more details).  If you want to portably save and restore signal
       masks, use sigsetjmp() and siglongjmp().

       The values of automatic variables are unspecified after a call to longjmp() if they
       meet all the following criteria:

       ?  they are local to the function that made the corresponding setjmp(3) call;

       ?  their values are changed between the calls to setjmp(3) and longjmp(); and

       ?  they are not declared as volatile.

       Analogous remarks apply for siglongjmp().

       longjmp()  and siglongjmp() make programs hard to understand and maintain.  If pos-
       sible an alternative should be used.

SEE ALSO
       setjmp(3), sigsetjmp(3)

COLOPHON
       This page is part of release 3.22 of the Linux man-pages project.  A description of
       the  project, and information about reporting bugs, can be found at http://www.ker-
       nel.org/doc/man-pages/.



                                  2009-01-13                        LONGJMP(3)

Generated by $Id: phpMan.php,v 4.55 2007/09/05 04:42:51 chedong Exp $ Author: Che Dong
On Apache
Under GNU General Public License
2017-12-12 23:36 @127.0.0.1 CrawledBy CCBot/2.0 (http://commoncrawl.org/faq/)
Valid XHTML 1.0!Valid CSS!