# strlen() under unicode.semantics

- Thread: https://externals.io/message/24170
- Original archive: https://news-web.php.net/php.internals/24170
- Started by Daniel Convissor on 2006-06-21T17:14:51+00:00
- Messages: 2
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## #24170 — Daniel Convissor — 2006-06-21T17:14:51+00:00

URL: https://externals.io/message/24170#24170

Hi:

Enjoyed Andrei's talk at the NYPHP Conference last week about unicode in 
PHP 6.  He mentioned that when unicode.semantics is on, `strlen()` will 
return the number of characters rather than the number of bytes, like 
mb_string() does or `strlen()` if mbstring.func_overload is on.

The hitch here is there are situations where one needs to know how many 
bytes are in a string.  Is there a function I've overlooked that does 
this or will do this, please?

Thanks,

--Dan

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## #24172 — Sara Golemon — 2006-06-21T19:50:03+00:00

URL: https://externals.io/message/24170#24172 · In reply to: #24170

> Enjoyed Andrei's talk at the NYPHP Conference last week about unicode in
> PHP 6.  He mentioned that when unicode.semantics is on, `strlen()` will
> return the number of characters rather than the number of bytes, like
> mb_string() does or `strlen()` if mbstring.func_overload is on.
>
> The hitch here is there are situations where one needs to know how many
> bytes are in a string.  Is there a function I've overlooked that does
> this or will do this, please?
>
My first question is: Why do you need to know the number of bytes occupied
by a textual string?  Is it because you want to work with binary strings?
Because that's still very possible:

Even with unicode.semantics=on, the binary string type may be explicitly
used in a few ways:

$a = b"This string contains an 0xF0 byte: \xF0";
$alen = strlen($a);

This being the simplest, the lowercase b (or u) characters denote a string
as being a binary (or unicode) string explicitly.  Leaving these specifiers
off yield whatever type is appropriate to unicode.semantics.

In other cases, such as reading from a binary mode file:

$fp = fopen('foo.bin', 'rb');
$str = fread($fp, 100);

The string returned is always returned as a binary string regardless of
unicode semantics.  When reading a text-mode file conversely:

$fp = fopen('foo.txt', 'rt');
$str = fread($fp, 100);

The type of string returned will depend on the unicode.semantics switch (in
order to ensure maximum BC, since scripts designed for windows already use
text mode to handle linebreak transformation).

-Sara