Re: About SUCCESS/FAILURE

> On 24 Dec 2014, at 23:53, Levi Morrison <levim@php.net> wrote: > > On Wed, Dec 24, 2014 at 4:27 PM, Johannes Schlüter > <johannes@schlueters.de> wrote: >> On Wed, 2014-12-24 at 11:13 -0700, Levi Morrison wrote: >> >>> I'm asking for specific things. The reason is that some API's do a >>> non-zero error code; the fact that they are negative is a detail that >>> we should not need to care about. >> >> My guess is that positive values more often might have a meaning ("5 >> items changed", "address 0x1234") whereas negative values less often >> have a meaning. Also passing -1 as parameter is more often invalid. Thus >> passing -1 is making debug output look more suspicious. >> >> (while there are cases where -1 is valid, see recent famous pid >> = fork(); /* ... */ kill(pid, SIGKILL); issue) > > I don't think this is the same use case as SUCCESS and FAILURE. Many > functions have an out parameter which is only valid when the returned > value is SUCCESS. This is not the same thing as an API which returns > an integer and just happen to embed error state in the negative range. > Notably, it doesn't make sense to do strpos() == SUCCESS > to check > success; these are different cases. My question is specifically > directed at the ones that use SUCCESS and FAILURE: which ones require > FAILURE to be negative instead of the normal UNIX-ism of non-zero? > > For the record I am in favor of an enum such as zend_status or > some > other name which indicates whether an operation succeeded or not for > the reasons already cited in this thread. I just don't see why FAILURE > needs to be negative and want to know why this is the case. Hi Levi, Again, I think the reason FAILURE is -1 is for consistency with other functions which use negative return values on error. Some functions return negative error codes, others just -1. Some functions return useful positive values, others just 0. But the idea is that all functions return a negative number on error, so you can use if (foo() < 0) to check for errors. That’s the point of making FAILURE be -1, AIUI. It makes it consistent with other things, like fork() or strpos(). Thanks. -- Andrea Faulds http://ajf.me/