> From: Ananyev, Konstantin [mailto:konstantin.anan...@intel.com] > Sent: Thursday, 2 December 2021 14.01 > > > > From: Thomas Monjalon [mailto:tho...@monjalon.net] > > > Sent: Thursday, 2 December 2021 08.19 > > > > > > 01/12/2021 22:37, Tyler Retzlaff: > > > > On Wed, Nov 24, 2021 at 06:04:56PM +0000, Bruce Richardson wrote: > > > > > if (ret < 0 && rte_errno == EAGAIN) > > > > > > > > i only urge that this be explicit as opposed to a range i.e. ret > == - > > > 1 > > > > preferred over ret < 0 > > > > > > I don't understand why you think it is important to limit return > value > > > to -1. > > > Why "if (ret == -1)" is better than "if (ret < 0)" ? > > > > Speaking for myself: > > > > For clarity. It leaves no doubt that "it failed" is represented by > the return value -1, and that the function does not return errno values > such as > > -EINVAL. > > > > But why '< 0' gives you less clarity? > Negative value means failure - seems perfectly clear to me.
I disagree: Negative value does not mean failure. Only -1 means failure. There is no -2 return value. There is no -EINVAL return value. Testing for (ret < 0) might confuse someone to think that other values than -1 could be returned as indication of failure, which is not the case when following the convention where the functions set errno and return -1 in case of failure. It would be different if following a convention where the functions return -errno in case of failure. In this case, testing (ret < 0) would be appropriate. So explicitly testing (ret == -1) clarifies which of the two conventions are relevant.
