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SETJMP(3P)                 POSIX Programmer's Manual                SETJMP(3P)
PROLOG
       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.
NAME
       setjmp -- set jump point for a non-local goto
SYNOPSIS
       #include <setjmp.h>
       int setjmp(jmp_buf env);
DESCRIPTION
       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.
       A  call to setjmp() shall save the calling environment in its env argu-
       ment for later use by longjmp().
       It is unspecified whether setjmp() is a macro or a function. If a macro
       definition  is  suppressed  in order to access an actual function, or a
       program defines an external identifier with the name setjmp, the behav-
       ior is undefined.
       An  application  shall ensure that an invocation of setjmp() appears in
       one of the following contexts only:
        *  The entire controlling  expression  of  a  selection  or  iteration
           statement
        *  One operand of a relational or equality operator with the other op-
           erand an integral constant expression, with the  resulting  expres-
           sion  being  the  entire  controlling  expression of a selection or
           iteration statement
        *  The operand of a unary '!'  operator with the resulting  expression
           being the entire controlling expression of a selection or iteration
        *  The  entire expression of an expression statement (possibly cast to
           void)
       If the invocation appears in any other context, the behavior  is  unde-
       fined.
RETURN VALUE
       If  the return is from a direct invocation, setjmp() shall return 0. If
       the return is from a call to longjmp(), setjmp() shall  return  a  non-
       zero value.
ERRORS
       No errors are defined.
       The following sections are informative.
EXAMPLES
       None.
APPLICATION USAGE
       In  general,  sigsetjmp()  is  more  useful  in dealing with errors and
       interrupts encountered in a low-level subroutine of a program.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       longjmp(), sigsetjmp()
       The Base Definitions volume of POSIX.1-2008, <setjmp.h>
COPYRIGHT
       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 Electri-
       cal 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.ker-
       nel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group                  2013                           SETJMP(3P)