(PHP 4 >= 4.0.6, PHP 5)
mb_substitute_character — Set/Get substitution character
mb_substitute_character() specifies substitution character when input character encoding is invalid or character code is not exist in output character encoding. Invalid characters may be substituted NULL(no output), string or integer value (Unicode character code value).
This setting affects mb_convert_encoding(), mb_convert_variables(), mb_output_handler(), and mb_send_mail().
substchar : Specify Unicode value as integer or specify as string as follows
Return Value: If substchar is set, it returns TRUE for success, otherwise returns FALSE. If substchar is not set, it returns Unicode value or "none"/"long".
Example#1 mb_substitute_character() example
<?php
/* Set with Unicode U+3013 (GETA MARK) */
mb_substitute_character(0x3013);
/* Set hex format */
mb_substitute_character("long");
/* Display current setting */
echo mb_substitute_character();
?>