Converts a string which is in the encoding used by GLib for filenames into a UTF-8 string.
Note that on Windows GLib uses UTF-8 for filenames; on other platforms, this function indirectly depends on the current locale.
The input string shall not contain nul characters even if the
len argument is positive. A nul character found inside the string
will result in error g_convert_error_illegal_sequence. If the source encoding is not UTF-8 and the conversion
output contains a nul character, the error g_convert_error_embedded_nul is set and the function returns
null. Use convert to produce output that may contain
embedded nul characters.
a string in the encoding for filenames
the length of the string, or -1 if the string is nul-terminated (Note that some encodings may allow nul bytes to occur inside strings.
In that case, using -1 for the
location to store the number of bytes in the input string that were successfully converted, or null.
Even if the conversion was successful, this may be less than
the number of bytes stored in the output buffer (not including the terminating nul).
The converted string, or null on an error.