WTF is wtf? (in WebKit code base)

Posted by Motti on Stack Overflow See other posts from Stack Overflow or by Motti
Published on 2009-05-07T11:40:58Z Indexed on 2010/05/31 4:52 UTC
Read the original article Hit count: 329

I downloaded Chromium's code base and ran across the WTF namespace.

namespace WTF {
    /*
     * C++'s idea of a reinterpret_cast lacks sufficient cojones.
     */
    template<typename TO, typename FROM>
    TO bitwise_cast(FROM in)
    {
        COMPILE_ASSERT(sizeof(TO) == sizeof(FROM), WTF_wtf_reinterpret_cast_sizeof_types_is_equal);
        union {
            FROM from;
            TO to;
        } u;
        u.from = in;
        return u.to;
    }
} // namespace WTF

Does this mean what I think it means? Could be so, the bitwise_cast implementation specified here will not compile if either TO or FROM is not a POD and is not (AFAIK) more powerful than C++ built in reinterpret_cast.

The only point of light I see here is the nobody seems to be using bitwise_cast in the Chromium project.


I see there's some legalese so I'll put in the little letters to keep out of trouble.

/*
 * Copyright (C) 2008 Apple Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

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