mchars_spec2cp
c = mchars_spec2cp(seq, len);
int mchars_spec2cp(const char *, size_t);
unicode = mchars_spec2cp(seq, seqlen);
uc = mchars_spec2cp(seq, sz);
if (mchars_spec2cp(stnam, inaml) >= 0)
istrue = mchars_spec2cp(start, len) != -1;
uc = mchars_spec2cp(seq, sz);
uc = mchars_spec2cp(cp, sz);
uc = mchars_spec2cp(seq, ssz);