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
If the invocation appears in any other context, the behavior is undefined.
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.
No errors are defined.
The following sections are informative.
In general, sigsetjmp() is more useful in dealing with errors
encountered in a low-level subroutine of a program.
longjmp() , sigsetjmp() , the Base Definitions volume
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