seekf
static off_t seekf(void *, off_t, int);
if (!(cshin = funopen2((void *) &SHIN, readf, writef, seekf, NULL,
if (!(cshout = funopen2((void *) &SHOUT, readf, writef, seekf, NULL,
if (!(csherr = funopen2((void *) &SHERR, readf, writef, seekf, NULL,