unescapeSegment
Unescapes a segment of an escaped string.
If any of the characters in @illegal_characters or the NUL character appears as an escaped character in @escaped_string, then that is an error and null will be returned. This is useful if you want to avoid for instance having a slash being expanded in an escaped path element, which might confuse pathname handling.
Note: NUL byte is not accepted in the output, in contrast to g_uri_unescape_bytes().
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.
Since
2.16
Parameters
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