2 * Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by John Birrell.
16 * 4. Neither the name of the author nor the names of any co-contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * $FreeBSD: src/lib/libc_r/uthread/uthread_autoinit.cc,v 1.3 2000/01/06 12:16:16 deischen Exp $
33 * $DragonFly: src/lib/libc_r/uthread/Attic/uthread_autoinit.cc,v 1.2 2003/06/17 04:26:48 dillon Exp $
37 * This module uses the magic of C++ static constructors to initialize the
38 * threads package at program start-up time.
40 * Note: Because of a bug in certain versions of "/usr/lib/c++rt0.o", you
41 * should _not_ enclose the body of this module in an "#ifdef _THREAD_SAFE"
45 extern "C" void _thread_init(void);
48 * First, we declare a class with a constructor.
50 class _thread_init_invoker {
52 _thread_init_invoker(); /* Constructor declaration. */
56 * Here is the definition of the constructor. All it does is call the
57 * threads initialization function, "_thread_init".
59 _thread_init_invoker::_thread_init_invoker()
65 * Here is a single, static instance of our "_thread_init_invoker" class.
66 * The mere existance of this instance will result in its constructor
67 * being called, automatically, at program start-up time.
69 static _thread_init_invoker the_thread_init_invoker;
72 * For the shared version of the threads library, the above is sufficient.
73 * But for the archive version of the library, we need a little bit more.
74 * Namely, we must arrange for this particular module to be pulled in from
75 * the archive library at link time. To accomplish that, we define and
76 * initialize a variable, "_thread_autoinit_dummy_decl". This variable is
77 * referenced (as an extern) from libc/stdlib/exit.c. This will always
78 * create a need for this module, ensuring that it is present in the
81 * We know that, if the user does _anything_ at all with threads, then the
82 * "uthread_init.c" module will be linked in. That is the case because
83 * "uthread_init.c" is the module that defines all of the global variables
84 * used by the threads library. The presence of "uthread_init.c" will, in
85 * turn, force this module to be linked in. And the presence of this module
86 * in the executable will result in the constructor being invoked, and
87 * "_thread_init" being called.
89 extern "C" int _thread_autoinit_dummy_decl; /* Declare with "C" linkage */
90 int _thread_autoinit_dummy_decl = 0;