On 03/28/2011 07:45 AM, tip-bot for Steven Rostedt wrote: > > WARN_ON_SMP(): Add comment to explain ({0;}) > > The define to use ({0;}) for the !CONFIG_SMP case of WARN_ON_SMP() > can be confusing. As the WARN_ON_SMP() needs to be a nop when > CONFIG_SMP is not set, including all its parameters must not be > evaluated, and that it must work as both a stand alone statement > and inside an if condition, we define it to a funky ({0;}). > > A simple "0" will not work as it causes gcc to give the warning that > the statement has no effect. > > As this strange definition has raised a few eyebrows from some > major kernel developers, it is wise to document why we create such > a work of art. > What the heck is wrong with the idiomatic and non-gcc-extension-using: ((void)0) ? -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html