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<?php mb_substitute_character("long"); var_dump( $conv = mb_convert_encoding( $bin = hex2bin("7FFFFFFF"), "UTF-8", "CP932" ), mb_check_encoding($bin, "CP932"), bin2hex(mb_convert_encoding($conv, "CP932", "UTF-8")) );
Output for 8.1.0 - 8.1.15, 8.2.0 - 8.2.2
string(4) "???" bool(false) string(8) "7f3f3f3f"
Output for 7.4.0 - 7.4.33, 8.0.1 - 8.0.27
string(19) "BAD+FFBAD+FFBAD+FF" bool(false) string(38) "7f4241442b46464241442b46464241442b4646"

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