A string, may be %NULL
Pointer to end of @escaped_string, may be %NULL
An optional string of illegal characters not to be allowed, may be %NULL
Return: an unescaped version of @escaped_string or %NULL on error. The returned string should be freed when no longer needed. As a special case if %NULL is given for @escaped_string, this function will return %NULL.
2.16
Unescapes a segment of an escaped string.
If any of the characters in @illegal_characters or the character zero appears as an escaped character in @escaped_string then that is an error and %NULL will be returned. This is useful it you want to avoid for instance having a slash being expanded in an escaped path element, which might confuse pathname handling.