#include <fontconfig/fontconfig.h> FcBool FcUtf8Len (FcChar8 *src, int len, int *nchar, int *wchar);
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 2.11.0