> On 24 Dec 2014, at 23:53, Levi Morrison <le...@php.net> wrote:
>
> On Wed, Dec 24, 2014 at 4:27 PM, Johannes Schlüter
> <johan...@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/
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