FcUtf8Len − count UTF‐8 encoded chars

#include <fontconfig.h>

FcBool FcUtf8Len (FcChar8 *src, int len, int *nchar, int

     Counts the number of Unicode chars in len bytes of src.
Places that count in nchar.  wchar contains 1, 2 or 4
depending on the number of bytes needed to hold the largest
unicode char counted.  The return value indicates whether
src is a well‐formed UTF8 string.

     Fontconfig version 2.4.2