ch_fpos
if (pos != ch_fpos) {
ch_fpos = pos;
ch_fpos += n;
nblocks = (ch_fpos + LBUFSIZE - 1) / LBUFSIZE;
if (!(ch_flags & CH_CANSEEK) && pos != ch_fpos &&
if (ch_fpos > pos)
while (ch_fpos < pos) {
ch_fpos = 0;
ch_fsize = ch_fpos;