Fb Utf8 Strlen - Hhvm

:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::

Count the number of UTF-8 code points in string, substituting U+FFFD for invalid sequences

Hack

function fb_utf8_strlen(
  string $input,
): int;

Parameters

string $input - The string.

Returns

int - - Returns the number of code points interpreting string as UTF-8.