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iconv_strlen

(PHP 5, PHP 7, PHP 8)

iconv_strlenReturns the character count of string

Description

iconv_strlen(string $string, ?string $encoding = null): int|false

In contrast to strlen(), iconv_strlen() counts the occurrences of characters in the given byte sequence string on the basis of the specified character set, the result of which is not necessarily identical to the length of the string in byte.

Parameters

string

The string.

encoding

If encoding parameter is omitted or null, string is assumed to be encoded in iconv.internal_encoding.

Return Values

Returns the character count of string, as an integer, or false if an error occurs during the encoding.

Changelog

Version Description
8.0.0 encoding is nullable now.

See Also

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User Contributed Notes 2 notes

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12
hfuecks @ nospam org
18 years ago
If iconv_strlen is passed a UTF-8 string containing badly formed sequences, it will return FALSE. This is in contrast to mb_strlen of the behaviour of utf8_decode, which strip out any bad sequences;

<?php
# UTF-8 string containing bad sequence: \xe9
$str = "I?t?rn?ti?n\xe9?liz?ti?n";

print
"mb_strlen: ".mb_strlen($str,'UTF-8')."\n";
print
"strlen/utf8_decode: ".strlen(utf8_decode($str))."\n";
print
"iconv_strlen: ".iconv_strlen($str,'UTF-8')."\n";
?>

Displays;

mb_strlen: 20
strlen/utf8_decode: 20
iconv_strlen:

(PHP 5.0.5)

As such it is being "stricter" than mb_strlen and it may mean you need to check for invalid sequences first. A quick way to check is to exploit the behaviour of the PCRE extension (see notes on pattern modifiers);

<?php
if (preg_match('/^.{1}/us',$str,$ar) != 1) {
die(
"string contains invalid UTF-8");
}
?>

A slower but stricter check (regex) can be found at: http://www.w3.org/International/questions/qa-forms-utf-8

Similiar applies to iconv_substr, iconv_strpos and iconv_strrpos
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4
sheryl
3 years ago
Notice there is a disconnect:
>If charset`parameter is omitted, str is assumed to be encoded in iconv.internal_encoding.

But clicking on the iconv.internal_encoding link (https://www.php.net/manual/en/iconv.configuration.php), the docs indicate that iconv.internal_encoding is deprecated since 5.6.
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