User`s guide

ldvjoctl
Purpose
Ldv-octl error codes are the same as for ioctl(); the number of bytes actually
transferred. -1 implies invalid handle, func, or device type. Only DOS device drivers
are allowed.
Syntax
int ldv-ioctl (int handle, unsigned char func, pVoid argdx, int argcx);
See Also
1dv.h
Returns
Parameters
The only valid values for ‘func’ are:
2
Read from device
3
Write to device
SLTA-10 Adapter User’s Guide A-5