/**
 * The vararg module is intended to facilitate vararg manipulation in D.
 * It should be interface compatible with the C module "stdarg," and the
 * two modules may share a common implementation if possible (as is done
 * here). 
 * Copyright: Copyright Digital Mars 2000 - 2009.
 * License:   <a href="http://www.boost.org/LICENSE_1_0.txt">Boost License 1.0</a>.
 * Authors:   Walter Bright, Hauke Duden
 *
 *          Copyright Digital Mars 2000 - 2009.
 * Distributed under the Boost Software License, Version 1.0.
 *    (See accompanying file LICENSE_1_0.txt or copy at
 *          http://www.boost.org/LICENSE_1_0.txt)
 */
module core.vararg;


/**
 * The base vararg list type.
 */
alias void* va_list;


/**
 * This function initializes the supplied argument pointer for subsequent
 * use by va_arg and va_end.
 *
 * Params:
 *  ap      = The argument pointer to initialize.
 *  paramn  = The identifier of the rightmost parameter in the function
 *            parameter list.
 */
void va_start(T) ( out va_list ap, ref T parmn )
{
    ap = cast(va_list) ( cast(void*) &parmn + ( ( T.sizeof + int.sizeof - 1 ) & ~( int.sizeof - 1 ) ) );
}

/**
 * This function returns the next argument in the sequence referenced by
 * the supplied argument pointer.  The argument pointer will be adjusted
 * to point to the next arggument in the sequence.
 *
 * Params:
 *  ap  = The argument pointer.
 *
 * Returns:
 *  The next argument in the sequence.  The result is undefined if ap
 *  does not point to a valid argument.
 */
T va_arg(T) ( ref va_list ap )
{
    T arg = *cast(T*) ap;
    ap = cast(va_list) ( cast(void*) ap + ( ( T.sizeof + int.sizeof - 1 ) & ~( int.sizeof - 1 ) ) );
    return arg;
}

/**
 * This function cleans up any resources allocated by va_start.  It is
 * currently a no-op and exists mostly for syntax compatibility with
 * the variadric argument functions for C.
 *
 * Params:
 *  ap  = The argument pointer.
 */
void va_end( va_list ap )
{

}


/**
 * This function copied the argument pointer src to dst.
 *
 * Params:
 *  src = The source pointer.
 *  dst = The destination pointer.
 */
void va_copy( out va_list dst, va_list src )
{
    dst = src;
}
