mfgrequired manufacturer string
mdlrequired model string
from 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.