/*
 * tclUnixThrd.c --
 *
 *	This file implements the UNIX-specific thread support.
 *
 * Copyright (c) 1991-1994 The Regents of the University of California.
 * Copyright (c) 1994-1997 Sun Microsystems, Inc.
 * Copyright (c) 2008 by George Peter Staplin
 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) $Id: tclUnixThrd.c,v 1.59 2008/07/24 21:54:42 nijtmans Exp $
 * RCS: @(#) $Id: tclUnixThrd.c,v 1.60 2008/08/13 23:08:39 das Exp $
 */

#include "tclInt.h"

#ifdef TCL_THREADS

#include "pthread.h"

void
TclpThreadExit(
    int status)
{
    pthread_exit(INT2PTR(status));
}
#endif /* TCL_THREADS */

#ifdef TCL_THREADS
/*
 *----------------------------------------------------------------------
 *
 * TclpThreadGetStackSize --
 *
 *	This procedure returns the size of the current thread's stack.
 *
 * Results:
 *	Stack size (in bytes?) or -1 for error or 0 for undeterminable.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

size_t
TclpThreadGetStackSize(void)
{
    size_t stackSize = 0;
#if defined(HAVE_PTHREAD_ATTR_SETSTACKSIZE) && defined(TclpPthreadGetAttrs)
    pthread_attr_t threadAttr;	/* This will hold the thread attributes for
				 * the current thread. */
#ifdef __GLIBC__
    /*
     * Fix for [Bug 1815573]
     *
     * DESCRIPTION:
     * On linux TclpPthreadGetAttrs (which is pthread_attr_get_np) may return
     * bogus values on the initial thread.
     *
     * ASSUMPTIONS:
     * There seems to be no api to determine if we are on the initial
     * thread. The simple scheme implemented here assumes:
     *   1. The first Tcl interp to be created lives in the initial thread. If
     *      this assumption is not true, the fix is to call
     *      TclpThreadGetStackSize from the initial thread previous to
     *      creating any Tcl interpreter. In this case, especially if another
     *      Tcl interpreter may be created in the initial thread, it might be
     *      better to enable the second branch in the #if below
     *   2. There will be no races in creating the first Tcl interp - ie, the
     *      second Tcl interp will be created only after the first call to
     *      Tcl_CreateInterp returns.
     *
     * These assumptions are satisfied by tclsh. Embedders on linux may want
     * to check their validity, and possibly adapt the code on failing to meet
     * them.
     */

    static int initialized = 0;

    if (!initialized) {
	initialized = 1;
	return 0;
    } else {
#else
    {
#endif
	if (pthread_attr_init(&threadAttr) != 0) {
	    return -1;
	}
	if (TclpPthreadGetAttrs(pthread_self(), &threadAttr) != 0) {
	    pthread_attr_destroy(&threadAttr);
	    return (size_t)-1;
	}
    }


    if (pthread_attr_getstacksize(&threadAttr, &stackSize) != 0) {
	pthread_attr_destroy(&threadAttr);
	return (size_t)-1;
    }
    pthread_attr_destroy(&threadAttr);
#elif defined(HAVE_PTHREAD_GET_STACKSIZE_NP)
#ifdef __APPLE__
    /*
     * On Darwin, the API below does not return the correct stack size for the
     * main thread (which is not a real pthread), so fallback to getrlimit().
     */
    if (!pthread_main_np())
#endif
    stackSize = pthread_get_stacksize_np(pthread_self());
#else
    /*
     * Cannot determine the real stack size of this thread. The caller might
     * want to try looking at the process accounting limits instead.
     */
#endif
    return stackSize;
}
#endif /* TCL_THREADS */

/*
 *----------------------------------------------------------------------
 *
 * Tcl_GetCurrentThread --
 *