mb_ereg_search (Matching a particular Unicode code point)

parsed

What is the problem of my $pattern or else?
I will be greatful if you could help, as finding the answer has taken 20 hours of searching Internet and thinking, to no avail.

Details are written after the code.

<html><head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
</head>
<body>

<?php
mb_internal_encoding("UTF-8");
mb_regex_encoding("UTF-8");

$string = "a";
$pattern="\\u0061";

mb_ereg_search_init($string);
if (mb_ereg_search($pattern)) {
	echo 'Pattern FOUND.<br>';
}else {
	echo 'Pattern NOT found.<br>';
 }
?>
</body></html>

Output: Pattern NOT found.

Details: I want to match the Unicode(UTF-8) character of "a" which is U+0061 (by Regular Expression Unicode Syntax of \u0061) with the letter "a". But the output is "Pattern NOT found."
What is the problem? Is there any other way to do that?

More Details: In the code above mb_ereg_search dosn't understand Unicode Regular Expression of "\u0061". It takes it as normal regular expression.
My ultimate goal is to check if a string is in some range of Unicode characters by an improved code. I am using php-4.3.11 with Windows XP, IIS.

kburger

I've never used mb_ereg_search, but I'm wondering if the '\' needs to be escaped.

$pattern = "\u0061";

parsed

Thank you kburger. I tried, it dosn't work.

parsed

What I've got up to now. Might be incorrect, Correct me if I am wrong:

Problems of the above code:
Regexp functions beginning with "ereg" implement a basic set of Regexp functionality. "mb_ereg_search" seems to be the same. So although we could have UTF-8 characters directly inside the patterns (I checked it with one pattern and worked for me) but what I wanted to do above isn't possible with mb_ereg_search.

What I should have done:
For better functionality we should use functions starting with "preg" (PCRE library), which are Perl-Compatible. So I should have:

$pattern="/\x{0061}/u"; in a function like "preg_match" or "preg_match_all".
You could use one or two backslashes, it dosn't matter, because both cases put the same string of "/\x{0061}/u" inside the Pattern argument of the function.
"u" at the end is is a Pattern Modifier by which pattern strings are treated as UTF-8.

So now the code should look like this:

<?php
$string = "a";
$pattern="/\x{0061}/u";
if (preg_match($pattern, $string, $matches)) {
	echo 'Pattern FOUND.<br>';
}else {
	echo 'Pattern NOT found.<br>';
 }
?>

Outoput: Pattern FOUND.

More details:
PCRE library: Beginning with PHP 4.2.0 its functions are enabled by default. The windows version of PHP has built in support for this extension. You do not need to load any additional extension in order to use these functions.
u (PCRE_UTF8) Modifier: This modifier is available from PHP 4.1.0 or greater on Unix and from PHP 4.2.3 on win32.

Ref:
PHP manual: "Regular Expression Functions (Perl-Compatible)"; "Pattern Modifiers"
PCRE man page
Perl Doc
RegexBuddy Regexp help