Re: Patch available for 3.0.6-pre-0

["Bart Schaefer" <schaefer@xxxxxxxxxxxxxxxx>]

On Apr 21,  4:52pm, Wayne Davison wrote:
} Subject: Re: Patch available for 3.0.6-pre-0
}
} Some of the added braces were to enclose some one-line macros that
} consist of an "if ... else ..."  block.  This makes it look like some
} of the ifs have braces that are enclosing only one line.

Exactly what warning were you silencing in this case?  The reason most
of those macros look like

    #define thing() if (! testthing) {;} else dothing

and *not*

    #define thing() if (testthing) dothing

is to prevent ambiguous/erroneous "else" situations.

My favorite approach is to write these kind of macros as

    #define thing() do { if (testthing) dothing; } while (0)

because that forms a semicolon-terminable statement yet still wraps the
macro body in braces.  The PERMALLOC { ... } LASTALLOC; blocks make use
of this trick, for example.  However, a previous maintainer chose not to
adopt that for macros that could be written as if (...) {;} else ..., so
I'd like to have a clear reason for changing them.

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com