Re: About SUCCESS/FAILURE

Hey: On Thu, Dec 25, 2014 at 12:38 PM, Pierre Joye <pierre.php@gmail.com> wrote: > On Thu, Dec 25, 2014 at 3:06 PM, Andrea Faulds <ajf@ajf.me> wrote: >> >>> 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() == SUCCESSW[[b`ê >>> ¥9ÕýJi.Ô 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(). > > doing if (foo() < 0 is exactly what should not be done, for any > function returning a status. Only FAILURE and SUCCESS should be used. > > Which value FAILURE and SUCCESS have is not really relevant here but > to actually be consistent. > > For example > > ZEND_API int zend_hash_del(HashTable *ht, zend_string *key) > > should actually be > > ZEND_API status zend_hash_del(HashTable *ht, zend_string *key) > > and its usage should be: > > if (zend_hash_del(ht, key) == FAILURE) { > ... > } > > Same for zend_parse_parameters and the likes. > > However functions like zval_update_class_constant > (http://lxr.php.net/xref/PHP_TRUNK/Zend/zend_API.c#1132 ) and all the > underlying functions, are confusing. Both the signature and the return > values should rely on FAILURE/SUCCESS. > > I think this is what Xinchen means too. Or at least this is what I > mean with unify the APIs. yes. and as a soft solution. we can change these functions which use success/failure return zend_status instead of int first. thanks > > Cheers, > -- > Pierre > > @pierrejoye | http://www.libgd.org -- Xinchen Hui @Laruence http://www.laruence.com/