+.PP
+A few special cases apply:
+.bP
+If the terminal database has not been initialized,
+these return an error.
+.bP
+The calls with a string parameter (\fBtgoto\fP, \fBtputs\fP)
+check if the string is null, or cancelled.
+Those return an error.
+.bP
+A call to \fBtgoto\fP using a capability with string parameters is an error.
+.bP
+A call to \fBtgoto\fP using a capability with no parameters,
+or more than two is an error.