82 lines
1.6 KiB
Text
82 lines
1.6 KiB
Text
.TH EXITS 2
|
|
.SH NAME
|
|
exits, _exits, atexit, atexitdont, terminate \- terminate process, process cleanup
|
|
.SH SYNOPSIS
|
|
.B #include <u.h>
|
|
.br
|
|
.B #include <libc.h>
|
|
.PP
|
|
.nf
|
|
.B
|
|
void _exits(char *msg)
|
|
.B
|
|
void exits(char *msg)
|
|
.PP
|
|
.B
|
|
int atexit(void(*)(void))
|
|
.B
|
|
void atexitdont(void(*)(void))
|
|
.fi
|
|
.SH DESCRIPTION
|
|
.I Exits
|
|
is the conventional way to terminate a process.
|
|
.I _Exits
|
|
is the underlying system call.
|
|
They
|
|
can never return.
|
|
.PP
|
|
.I Msg
|
|
conventionally includes a brief (maximum length
|
|
.BR 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
|
|
.IR wait (2).
|
|
.PP
|
|
Before calling
|
|
.I _exits
|
|
with
|
|
.I msg
|
|
as an argument,
|
|
.I exits
|
|
calls in reverse order all the functions
|
|
recorded by
|
|
.IR atexit .
|
|
.PP
|
|
.I Atexit
|
|
records
|
|
.I fn
|
|
as a function to be called by
|
|
.IR 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,
|
|
.I exits
|
|
only calls those
|
|
.IR atexit -registered
|
|
functions that were registered by the same
|
|
process as that calling
|
|
.IR exits .
|
|
.PP
|
|
Calling
|
|
.I atexit
|
|
twice (or more) with the same function argument causes
|
|
.I exits
|
|
to invoke the function twice (or more).
|
|
.PP
|
|
There is a limit to the number of exit functions
|
|
that will be recorded;
|
|
.I atexit
|
|
returns 0 if that limit has been reached.
|
|
.PP
|
|
.I Atexitdont
|
|
cancels a previous registration of an exit function.
|
|
.SH SOURCE
|
|
.B /sys/src/libc/port/exits.c
|
|
.br
|
|
.B /sys/src/libc/port/atexit.c
|
|
.SH "SEE ALSO"
|
|
.IR fork (2),
|
|
.IR wait (2)
|