...
void
...
exit(int
...
status)
...
The
...
exit
...
function
...
is
...
used
...
for
...
normal
...
program
...
termination
...
to
...
occur.
...
If more than one call to exit()
...
is
...
executed
...
by
...
a
...
program,
...
the
...
behavior
...
is
...
undefined.
...
This
...
type
...
of
...
situation
...
typically
...
only
...
happens
...
when
...
functions
...
are
...
registered
...
with
...
atexit(),
...
a
...
function
...
that
...
causes
...
the
...
functions
...
registered
...
to
...
it
...
to
...
be
...
called
...
with
...
when
...
the
...
program
...
exits.
...
If
...
a
...
function
...
called
...
due
...
to
...
being
...
registered
...
with
...
atexit()
...
has
...
an
...
exit()
...
call
...
in
...
it
...
there
...
is
...
undefined
...
behavior.
...
Non-Compliant
...
Code
...
Example
...
In
...
this
...
code
...
as
...
the
...
main
...
function
...
exits
...
two
...
functions
...
registered
...
with
...
atexit()
...
are
...
called.
...
Given
...
the
...
define
...
statement
...
exitearly=1
...
the
...
program
...
calls
...
exit
...
within
...
the
...
first
...
function
...
called
...
in
...
the
...
atexit()
...
cycle.
...
The
...
behavior
...
that
...
follows
...
is
...
undefined:
...
some
...
implementations
...
will
...
ignore
...
the
...
second
...
call
...
to
...
exit
...
and
...
just
...
continue
...
calling
...
the
...
atexit
...
functions
...
in
...
the
...
appropriate
...
order.
...
Other
...
implementations
...
will
...
enter
...
an
...
infinite
...
loop
...
with
...
the
...
atexit
...
functions
...
being
...
called
...
repeatedly.
| Code Block | ||
|---|---|---|
| ||
\#include <stdio.h> \#include <stdlib.h> \#define exitearly 1 void exit1 (void) { printf("Exit second.\n"); } void exit2 (void) { printf("Exit first.\n"); if(exitearly) { exit(1); } } int main () { atexit (exit1); atexit (exit2); printf("In main\n"); exit(1); return 0; } ? |
Compliant
...
Code
...
To
...
have
...
functionality
...
where
...
the
...
program
...
can
...
quit
...
from
...
within
...
a
...
function
...
registered
...
by
...
at_exit()
...
one
...
has
...
to
...
use
...
a
...
function
...
used
...
for
...
abnormal
...
termination
...
such
...
as
...
_exit()
...
or
...
abort().
...
From
...
the
...
man
...
page
...
of
...
_exit():
...
The
...
function
...
_exit
...
terminates
...
the
...
calling
...
process
...
"immediately".
...
Any
...
open
...
file
...
descriptors
...
belonging
...
to
...
the
...
process
...
are
...
closed;
...
any
...
children
...
of
...
the
...
process
...
are
...
inherited
...
by
...
process
...
1,
...
init,
...
and
...
the
...
process's
...
parent
...
is
...
sent
...
a
...
SIGCHLD
...
signal.
| Code Block | ||
|---|---|---|
| ||
\#include <stdio.h> \#include <stdlib.h> \#define exitearly 1 void exit1 (void) { printf("Exit second.\n"); } void exit2 (void) { printf("Exit first.\n"); if(exitearly) { \ _exit(1); } } int main () { atexit (exit1); atexit (exit2); printf("In main\n"); exit(1); return 0; } ? |
Risk
...
Assessment
...
Rule | Severity | Likelihood | Remediation Cost | Priority | Level |
|---|---|---|---|---|---|
MSC31-C | 1 (low) | 1 (unlikely) | 3(low) | P3 | L3 |
References
| Wiki Markup |
|---|
\[[ISO/IEC 9899-1999|AA. C References#ISO/IEC 9899-1999]\] Section 7.20.4.3, "The exit function" |
...