how is echo implemented in php

[Water Cooler v2]

When used with the command line interface, echo writes to the stdout,
whereas in a Web environment, it writes to the response stream. How is
it implemented inside PHP?

Does it write to a stream?

[Rik]

On Tue, 14 Aug 2007 22:58:40 +0200, Water Cooler v2 <wt*****@yahoo.com>
wrote:

When used with the command line interface, echo writes to the stdout,
whereas in a Web environment, it writes to the response stream. How is
it implemented inside PHP?

I really couldn't tell you, to see how it is emplemented exactly you'll
have to take a look at the source I suppose. For more information how it
works on the command line:
<http://nl3.php.net/manual/en/features.commandline.php>

Does it write to a stream?

Well, everything in PHP can be reached 'as a stream', how the inner
workings are is offcourse a different story. This tidbit of information
leads me to believe it is just written to the output stream, where this is
actually directed is not really decided there:

<http://nl3.php.net/manual/en/wrappers.php.php>:
"php://output allows you to write to the output buffer mechanism in the
same way as print() and echo()."
--
Rik Wasmus

[Water Cooler v2]

On Aug 15, 2:14 am, Rik <[e-mail]:

On Tue, 14 Aug 2007 22:58:40 +0200, Water Cooler v2 <[e-mail]>
wrote:

When used with the command line interface, echo writes to the stdout,
whereas in a Web environment, it writes to the response stream. How is
it implemented inside PHP?

I really couldn't tell you, to see how it is emplemented exactly you'll
have to take a look at the source I suppose. For more information how it
works on the command line:
<http://nl3.php.net/manual/en/features.commandline.php>

Does it write to a stream?

Well, everything in PHP can be reached 'as a stream', how the inner
workings are is offcourse a different story. This tidbit of information
leads me to believe it is just written to the output stream, where this is
actually directed is not really decided there:

<http://nl3.php.net/manual/en/wrappers.php.php>:
"php://output allows you to write to the output buffer mechanism in the
same way as print() and echo()."
--
Rik Wasmus

I downloaded the source on my Windows XP Pro machine. Can you please
tell me in which folder I can find the definition of the function?

[Ivan Marsh]

On Tue, 14 Aug 2007 13:58:40 -0700, Water Cooler v2 wrote:

When used with the command line interface, echo writes to the stdout,
whereas in a Web environment, it writes to the response stream. How is
it implemented inside PHP?

Does it write to a stream?

I'm assuming it's written to stdout no matter where it's run... as with
CGI applications, the browser interface IS stdout and the webserver
controls where the output goes.

[Rik]

On Tue, 14 Aug 2007 23:17:52 +0200, Water Cooler v2 <wt*****@yahoo.com>
wrote:

On Aug 15, 2:14 am, Rik <[e-mail]:

>On Tue, 14 Aug 2007 22:58:40 +0200, Water Cooler v2 <[e-mail]>
wrote:

When used with the command line interface, echo writes to the stdout,
whereas in a Web environment, it writes to the response stream. How is
it implemented inside PHP?

I really couldn't tell you, to see how it is emplemented exactly you'll
have to take a look at the source I suppose.

I downloaded the source on my Windows XP Pro machine. Can you please
tell me in which folder I can find the definition of the function?

It is not a function, it's a language construct. And sorry, can't tell you
where to find it, you'll have to search for it yourself, or possibly ask
one of the developers.
--
Rik Wasmus

[gosha bine]

On 14.08.2007 22:58 Water Cooler v2 wrote:

When used with the command line interface, echo writes to the stdout,
whereas in a Web environment, it writes to the response stream. How is
it implemented inside PHP?

Does it write to a stream?

If you interested in php internals, I'd recommend browsing their LXR
site. For 'echo', start here

http://lxr.php.net/source/ZendEngine2/zend_vm_def.h#883

and follow the links.

--
gosha bine

makrell ~ http://www.tagarga.com/blok/makrell
php done right ;) http://code.google.com/p/pihipi

[Toby A Inkster]

Ivan Marsh wrote:

I'm assuming it's written to stdout no matter where it's run... as with
CGI applications, the browser interface IS stdout and the webserver
controls where the output goes.

That would be my assumption too, which the added note that on Apache,
mod_php hooks into the web server itself, so probably has something to do
with informing Apache that stdout should be sent to the HTTP client.

--
Toby A Inkster BSc (Hons) ARCS
[Geek of HTML/SQL/Perl/PHP/Python/Apache/Linux]
[OS: Linux 2.6.12-12mdksmp, up 55 days, 11:51.]

Fake Steve is Dead; Long Live Fake Bob!
http://tobyinkster.co.uk/blog/2007/08/13/fake-bob/