Messages in this thread | | | Date | Tue, 16 Oct 2018 21:29:28 +0200 | From | Uwe Kleine-König <> | Subject | Re: [PATCH RFC] err.h: document that PTR_ERR should only be used if IS_ERR returns true |
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On Tue, Oct 16, 2018 at 07:06:51PM +0100, Al Viro wrote: > On Mon, Oct 15, 2018 at 11:37:08AM +0200, Alessandro Rubini wrote: > > > OTOH I admit you can compare any value with -EINVAL, after PTR_ERR. > > But in general you first detect the error condition and then split > > among error (or print a message according to the exact value. > > if (IS_ERR(p) && PTR_ERR(p) == -ENOENT) > instead of > if (p == ERR_PTR(-ENOENT)) > > is ugly, obfuscating what's going on for no good reason and I'm going > to keep killing those every time I run into one...
And what do you do if you see a
p = somefunc(...); if (PTR_ERR(p) == -ENOENT)
without first checking for IS_ERR(p)? Another alternative is
if (PTR_ERR_OR_ZERO(p) == -ENOENT)
? In your eyes, should they all be converted to
if (p == ERR_PTR(-ENOENT))
?
Best regards Uwe
-- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
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