longjmp

       #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 inter-
       rupts encountered 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 exe-
       cution  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 nonzero savesigs flag, siglongjmp()  also  restores  the  signal
       mask that was saved by sigsetjmp(3).

RETURN VALUE
       These functions never return.

ATTRIBUTES
       For   an   explanation   of   the  terms  used  in  this  section,  see
       attributes(7).

       +------------------------+---------------+---------+
       |Interface               | Attribute     | Value   |
       +------------------------+---------------+---------+
       |longjmp(), siglongjmp() | Thread safety | MT-Safe |
       +------------------------+---------------+---------+

CONFORMING TO
       longjmp(): POSIX.1-2001, POSIX.1-2008, C89, C99.

       siglongjmp(): POSIX.1-2001, POSIX.1-2008.

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

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

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


COLOPHON
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                                  2015-08-08                        LONGJMP(3)
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