NAME

       setjmp - set jump point for a non-local goto

SYNOPSIS

       #include <setjmp.h>

       int setjmp(jmp_buf env);

DESCRIPTION

       A call to setjmp() shall save the calling environment in its env argument 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
       behavior 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  operand  an  integral  constant
          expression,  with  the  resulting expression 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 undefined.

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 IEEE Std 1003.1-2001, <setjmp.h>

COPYRIGHT

       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 .

IEEE/The Open Group                                   2003                                             SETJMP(P)