[ Version ( since = "2.52" ) ]
public string make_valid (ssize_t len = -1)

If the provided string is valid UTF-8, return a copy of it.

If not, return a copy in which bytes that could not be interpreted as valid Unicode are replaced with the Unicode replacement character ( U+FFFD).

For example, this is an appropriate function to use if you have received a string that was incorrectly declared to be UTF-8, and you need a valid UTF-8 version of it that can be logged or displayed to the user, with the assumption that it is close enough to ASCII or UTF-8 to be mostly readable as-is.



the maximum length of str to use, in bytes. If len < 0, then the string is nul-terminated.


string to coerce into UTF-8


a valid UTF-8 string whose content resembles str