EXITS(2)EXITS(2)
NAME
exits, _exits, atexit, atexitdont, terminate – terminate process, process cleanup
SYNOPSIS
#include <u.h>
#include <libc.h>
void _exits(char *msg)
void exits(char *msg)
int atexit(void(*)(void))
void atexitdont(void(*)(void))
DESCRIPTION
Exits
is the conventional way to terminate a process.
_Exits
is the underlying system call.
They
can never return.
Msg
conventionally includes a brief (maximum length
ERRLEN)
explanation of the reason for
exiting, or a null pointer or empty string to indicate normal termination.
The string is passed to the parent process, prefixed by the name and process
id of the exiting process, when the parent does a
wait(2).
Before calling
_exits
with
msg
as an argument,
exits
calls in reverse order all the functions
recorded by
atexit.
Atexit
records
fn
as a function to be called by
exits.
It returns zero if it failed,
nonzero otherwise.
A typical use is to register a cleanup routine for an I/O package.
To simplify programs that fork or share memory,
exits
only calls those
atexit-registered
functions that were registered by the same
process as that calling
exits.
Calling
atexit
twice (or more) with the same function argument causes
exits
to invoke the function twice (or more).
There is a limit to the number of exit functions
that will be recorded;
atexit
returns 0 if that limit has been reached.
Atexitdont
cancels a previous registration of an exit function.
SOURCE
/sys/src/libc/port/exits.c
/sys/src/libc/port/atexit.c
SEE ALSO
fork(2),
wait(2)