It is possible to set up new programmer-defined field types. See the
\fBform_fieldtype\fR(3X) manual page.
.SH RETURN VALUE
The functions \fBfield_type\fR and \fBfield_arg\fR return \fBNULL\fR on
error. The function \fBset_field_type\fR returns one of the following:
.TP 5
It is possible to set up new programmer-defined field types. See the
\fBform_fieldtype\fR(3X) manual page.
.SH RETURN VALUE
The functions \fBfield_type\fR and \fBfield_arg\fR return \fBNULL\fR on
error. The function \fBset_field_type\fR returns one of the following:
.TP 5