readf
static ssize_t readf(void *, void *, size_t);
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,