On section 6.3.5 - "A Complete Multibyte Conversion Example" the example 
describe an algorithm to convert an NUL-terminated multibyte character string at 
into an equivalent wide character string. It does:

1. read from input file to temp buffer
2. convert characters in temp buffer
3. write to output file the converted characters
4. go to step one, but first copy incomplete sequence to start of temp buffer

The pass four is implemented by a memmove(), taking an incomplete at the end of 
the buffer and repositioning it at the start of the buffer.

ERROR:
------
 The aforementioned memmove() has its parameters inverted, because it`s
 not putting the remaining characters in the beginning of the buffer.

Instead of:
    memmove (inp, buffer, filled);

It should obviously be:
    memmove (buffer, inp, filled);