.\" This file is part of the Public Domain C Library (PDCLib).
.\" Permission is granted to use, modify, and / or redistribute at will.
.\"
.Dd
.Dt exit 3
.Os
.\"
.Sh NAME
.Nm exit
.Nd terminates the process
.\"
.Sh SYNOPSIS
.In stdlib.h
.Fn "noreturn void exit" "int status"
.Fn "noreturn void quick_exit" "int status"
.Fn "noreturn void _Exit" "int exitcode"
.\"
.Sh DESCRIPTION
Calling any of these three functions terminates the current process, returning 
the exit code passed as a parameter. The interpretation of the exit code is 
undefined, except that 0 or
.Dv EXIT_SUCCESS
shall indicate successful completion and
.Dv EXIT_FAILURE
shall indicate a non-successful completion.
.\"
.Pp
.Fn exit
first destroys all objects with C++ thread local storage duration (the C 
standard leaves whether or not thread local objects are destroyed or not 
undefined). Next, the destructors of all C++ objects of static storage duration 
are invoked along with all functions passed to
.Fn atexit 
in reverse order of registration (the time of registration for C++ objects of 
static storage duration is taken to be the time at which the constructor 
completes). It then flushes all open
.Vt FILE
streams with unwritten data and closes them. Finally, files created by
.Fn tmpfile
are removed, before handing control back to the host environment. Note in 
particular that functions registered with
.Fn at_quick_exit
are
.Sy not
called.
.\"
.Pp
.Fn quick_exit
invokes any functions registered with
.Fn at_quick_exit
in reverse order of registration, then returns control to the host 
environment by calling
.Fn _Exit .
No signal handlers are called, nor are any functions registered with
.Fn atexit .
.\"
.Pp
.Fn _Exit
returns control to the controlling environment without invoking any functions
registered by
.Fn atexit ,
.Fn at_quick_exit ,
any signal handlers, or the destructors of any thread local objects or C++ 
objects of static storage duration. Whether or not any open 
.Vt FILE
streams with unwritten data are flushed or not is undefined.
.\"
.Pp
The result of aborting a call to 
.Fn exit
or
.Fn quick_exit
by use of 
.Fn longjmp
is undefined. If any function or destructor invoked by
.Fn exit
or
.Fn quick_exit
should throw, 
.Fn std::terminate
is invoked.
.\"
.Pp
Undefined behaviour results if, while a call to
.Fn exit
or
.Fn quick_exit
is in progress, a call to 
.Fn exit
or
.Fn quick_exit
is made. 
.\"
.Sh IMPLEMENTATION NOTES
PDCLib implements the process of flushing streams in
.Fn _Exit ,
and therefore
.Fn exit
calls it after all
.Fn atexit
handlers have been invoked.
.\"
.Sh SEE ALSO
.Xr abort 3
.Xr atexit 3
.Xr at_quick_exit 3
.\"
.Sh STANDARDS
.Fn exit
is first defined in
.St -isoC-90 ;
.Fn _Exit
was introduced in
.St -isoC-99 .
.Fn quick_exit
was introduced in
.St -isoC-11 
and
ISO/IEC 14882:2011 "C++ 2011" .