Mozilla

Documentation

Returns the number of the byte pointed to by the given position. Determines whether the byte at the given position is the 1st, 2nd, 3rd or 4th byte of the character at that position. The pstr pointer must point to the first byte of any preceding character in the string. The pos position must be greater than zero, and is the index into pstr plus one. I.e. the byte at pstr[0] has pos 1. If pos points to the only byte in a single-byte character, this function returns zero. Otherwise, if pos points to the 1st byte, it returns 1. If pos points to the 2nd byte, it returns 2. And so on.