readf
static int readf(void *, char *, int);
if (!(cshin = funopen((void *) &SHIN, readf, writef, seekf, closef)))
if (!(cshout = funopen((void *) &SHOUT, readf, writef, seekf, closef)))
if (!(csherr = funopen((void *) &SHERR, readf, writef, seekf, closef)))