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dir: /doc/man3/setjmp.3/

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.TH SETJMP 3
.SH NAME
setjmp - non-local jumps
.SH SYNOPSIS
#include <setjmp.h>

.nf
int setjmp(jmp_buf env)
void longjmp(jmp_buf env, int val)
.fi
.SH DESCRIPTION
The
.BR setjmp ()
function saves it calling environment in its argument
.I env
for later use by the
.BR longjmp .

The
.BR longjmp ()
function restores the environment saved
by the most recent invocation of
.B setjmp
in the same invocation of the program
with the corresponding
.I env
as argument.

If there has been no such invocation,
or if the function containing the invocation of
.B setjmp
has terminated execution,
or if the invocation of
.B setjmp
was within the scope of an identifier with variably modified type
and execution has left that scope in interim,
the behavior is undefined.
.SH RETURN VALUE
If the return is from a direct invocation,
.B setjmp
shall return the value zero.
If the return is from a call to
.BR longjmp ,
.B setjmp
shall return a nonzero value.

After the function
.B longjmp
is called,
program execution continues as
if the corresponding invocation of
.B setjmp
has just returned the value specified by
.IR val .
The function
.B longjmp
shall not cause the function
.B setjmp
to return the value 0.
If
.I val
is set to 0,
.B setjmp
shall return the value 1.
.SH STANDARDS
.nf
ISO/IEC 9899:1999 Section 7.13.1.1 Paragraph 1,2,3
ISO/IEC 9899:1999 Section 7.13.2.1 Paragraph 1,2,3,4
.fi
.SH SEE ALSO
.BR setjmp.h (3)