[Ffmpeg-devel] Revised os2.diff
Thu May 5 09:50:47 CEST 2005
On Sun, May 01, 2005 at 06:26:41PM +0300, Matti Hamalainen wrote:
> On Sun, 1 May 2005, Fred Rothganger wrote:
> > I use spaces before the # regularly with impunity. Compiles ok
> > under bothe gcc and msvc. However, if you want spaces, I think
> > the style of putting them after the # is nicer.
> Some preprocessors (GNU cpp too, in traditional mode) actually _require_
> that the preprocessor directive starts from the first column of line
> (whitespaces are allowed after '#' though). I don't know if this has any
> relevance to FFMPEG project, but I think it's a widely used practice to
> do the right way(tm).
That document says (in the preprocessing lanuage section) that "white
space is allowed before and after the #".
That one says that the '#' has to be in the first column. It may be
specific to the LPC preprocessor implementation, though.
> I couldn't find any references to C standards though,
The C99 draft allows whitespace both before and after the #. There is
a constraint that the only whitespace characters allowed after the #
are spaces and horizontal tabs. Before the # you can have anything
that counts as whitespace, including things like form feeds and vtabs.
That said, I'd recommend putting the # in the first column anyway just
to be safe. It might also benefit syntax highlighters or other code
processors that aren't as robust as a compiler might be.
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