Date: Sun, 4 May 2008 17:47:34 +0200 From: Roland Smith <rsmith@xs4all.nl> To: Unga <unga888@yahoo.com> Cc: Patrick Clochesy <pcloches@gmail.com>, freebsd-questions@freebsd.org Subject: Re: Variable arg function question Message-ID: <20080504154734.GA98310@slackbox.xs4all.nl> In-Reply-To: <630200.71551.qm@web57011.mail.re3.yahoo.com> References: <20080504144532.GA56965@slackbox.xs4all.nl> <630200.71551.qm@web57011.mail.re3.yahoo.com>
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On Sun, May 04, 2008 at 08:34:30AM -0700, Unga wrote:
>=20
> --- Roland Smith <rsmith@xs4all.nl> wrote:
>=20
> > On Sun, May 04, 2008 at 07:02:36AM -0700, Patrick
> > Clochesy wrote:
> > > What about using a macro (...) in front of the
> > function to csll it which=20
> > > passes __VARARGS__, NULL to ensure there is always
> > a trailing NULL? I think=20
> > > this would at least work in GCC... Can' test on my
> > phone though.
> >=20
> > That's a good idea. If one uses __VA_ARGS__ instead
> > of __VARARGS__, it
> > should work with any C99 compliant compiler,
> > including gcc.
> I gave it a try, but I cannot get it to work:
> (As per above wikipedia example)
>=20
> void realdprintf (char const *file, int line, char
> const *fmt, ...);=20
> #define dprintf(...) realdprintf(__FILE__, __LINE__,
> __VA_ARGS__)
>=20
> To solve my problem, I must be able to indicate the
> end of the arg list, may be by a empty string (""),
> but GNU C compiler does not allow to specify anything
> after the ... .
Try something like what Patrick suggested:
#define f(...) _f(__VA_ARGS__,NULL)
Roland
--=20
R.F.Smith http://www.xs4all.nl/~rsmith/
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