```{index} single: native_is_utf8; Encode function ``` ```{index} single: Encode::native_is_utf8; Perl function ``` # native_is_utf8 Return true if the scalar carries the `SVf_UTF8` flag. ## Synopsis ```perl my $flagged = is_utf8($string); my $flagged = is_utf8($string, $check); ``` With one argument, `is_utf8` reports the flag as-is. With a true `$check`, the bytes are also validated as UTF-8; a flagged scalar whose bytes are not valid UTF-8 returns false. This is a low-level diagnostic. Regular Perl code should not need it — the flag is an internal implementation detail, and the right place to think about "is this text" is at I/O boundaries with `encode`/`decode`. ## Differences from upstream Fully compatible with upstream. Covered by `t/81-xs-native/Encode/080-utf8-flags.t`.