exits(2) [plan9 man page]

EXITS(2)							System Calls Manual							  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))

       /* Alef only */

       void _exits(byte *msg)

       void exits(byte *msg)

       void terminate(byte *msg)

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.

Alef
       In  Alef,  the system call _exits is the same, but its use is discouraged because the run-time system needs to maintain consistency; termi-
       nate and exits are the recommended routines.  Terminate is called automatically when a task or proc returns from its main function; it  may
       also  be  called  explicitly.  In either case, it frees resources private to the task (which may be the implicit main task within the proc)
       and terminates that task.  If that task is the last one in the proc, resources private to the proc are then freed.  If  that  proc  is  the
       last  one in the program, it calls exits.  Exits should only be called in the last proc of a program; it calls any atexit functions (regis-
       tered by any proc) and then calls _exits.

       In Alef, atexit and atexitdont behave the same as in C.

SOURCE

       /sys/src/libc/port/atexit.c

SEE ALSO

       fork(2), wait(2)

																	  EXITS(2)

Check Out this Related Man Page

atexit(3C)						   Standard C Library Functions 						atexit(3C)

NAME

       atexit - register a function to run at process termination or object unloading

SYNOPSIS

       #include <stdlib.h>

       int atexit(void (*func)(void));

DESCRIPTION

       The atexit() function registers the function pointed to by func to be called without arguments on normal termination of the program or when
       the object defining the function is unloaded.

       Normal termination occurs by either a call to the exit(3C) function or a return from  main().  Object  unloading  occurs  when  a  call	to
       dlclose(3C) results in the object becoming unreferenced.

       The  number  of functions that may be registered with atexit() is limited only by available memory (refer to the _SC_ATEXIT_MAX argument of
       sysconf(3C)).

       After a successful call to any of the exec(2) functions, any functions previously registered by atexit() are no longer registered.

       On process exit, functions are called in the reverse order of their registration. On  object  unloading,  any  functions  belonging  to	an
       unloadable object are called in the reverse order of their registration.

RETURN VALUES

       Upon successful completion, the atexit() function returns 0. Otherwise, it returns a non-zero value.

ERRORS

       The atexit() function may fail if:

       ENOMEM	       Insufficient storage space is available.

USAGE

       The functions registered by a call to atexit() must return to ensure that all registered functions are called.

       There is no way for an application to tell how many functions have already been registered with atexit().

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Safe			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       exec(2), dlclose(3C), exit(3C), sysconf(3C), attributes(5)

SunOS 5.10							    25 May 2001 							atexit(3C)

Linux and UNIX Man Pages

exits(2) [plan9 man page]

Check Out this Related Man Page