Stut schreef:
> On 20 Nov 2008, at 01:29, Rene Fournier wrote:
>> I'm trying to understand something about fread(). I'm using fread() on
>> an incoming socket stream that will send, for example, 26630 characters:
>>
>> while ( ($buf=fread($read[$i], 8192)) != '' ) {
>> $sock_data .= $buf;
>> usleep(1000);
>> echo ".";
>> }
>> echo ",";
>>
>>
>> As soon as the socket client sends the data, immediately the server
>> will echo:
>>
>> ................................................................................................................................................
>>
>>
>> Then wait nearly a minute, and echo:
>>
>> ,
>>
>> So my question is, why does fread wait if there is nothing more to
>> read? Shouldn't it return immediately? (That's what I want.) And as
>> for the delay, it's there so that if the incoming data is a little
>> slow, it has time to catch up with fread. Thanks.
>
> As Craige already mentioned, fread will read bytes until it meets an EOF
> so unless the other side sends one or closes the socket fread will wait
> for the number of characters you've asked for (8192) or a timeout (which
> is the delay you're seeing). In other words it's not detecting the end
> of the data, it's just timing out waiting for more.
>
> You ideally want to have the other side tell you how many bytes it's
> going to send. If you can't do that then hopefully the data you're
> receiving has some sort of structure so you can check the incoming data
> for some terminating string. If not then you've got a problem that can't
> be reliably solved. You could mess around with the timeout and/or make
> use of functions like socket_select to check for waiting data, but what
> you'll end up with will be problematic on slow connections and generally
> unreliable.
good stuff from Stut & Craige ... I just wondered, Im pretty sure that the
usleep(1000) is completely superfluous. fread() will read to the buffer length
or EOF regardless of how slow the stream trickles in (obviously it may timeout
if nothing trickles in for ages but that's a different issue and not solved
with a usleep() AFAICT).
>
> -Stut
>
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