Length of a string displayable in C

Does anyone know if there is a function in lib or libX11 which returns the number of characters? (strlen () is not appropriate because it returns the number of bytes)
Eg "/hame/big/proj$", strlen () returns me 19 while only 15 characters 'to', 'é', 'i', 'O' which are 2octets characters.

I made a function:

Code:

---

unsigned int StringLength(char *str)
  (
    unsigned int nb;
    char c, flg;

    for (nb = 0, flg = 0; (c = *str) != '\0'; ++str, ++pos) {
      if (isprint(c) != 0){ // classical character display                                                                                     
        flg = 0;
        ++nb;
      )
      else if (flg == 0) // if it was the first byte of a 2octets character 
        ++flg;
      else if (flg == 1) { // 2nd characters display the 2octets
        ++nb;
        flg = 0;
      )
    )
    if (flg == 1) // If the last character was the 2nd byte character 2octets
      ++nb;
    return (nb);
  )

---

it's utf8:

Code:

---

size_t strlen_utf8 (const char * const s)
  (
    size_t i = 0;
    size_t j = 0;
 
    while (s[i]) 
    (
        if ((s[i] & 0xc0) != 0x80) 
          j++;
       
        i++;
    )
 
    return j;
  )

---

If your string is a wide char (wchar_t-based), the function is wcslen
If your string is encoded in utf8 mblen should do the trick.

What a solution... Wow. Thank you.