required manufacturer string
required model string
previous device number found in search, or NULL for new search
This walks through the list of parallel port devices looking for a device whose 'MFG' string matches mfg and whose 'MDL' string matches mdl in their IEEE 1284 Device ID.
When a device is found matching those requirements, its device number is returned; if there is no matching device, a negative value is returned.
A new search it initiated by passing NULL as the from argument. If from is not NULL, the search continues from that device.