OpenDriver Open the device driver specified by name

#include <Devices.h> Device Manager

OSErr OpenDriver( driverName, refNum );

Str255 driverName ; address of device driver name

short *refNum ; receives device driver reference number

returns Error Code; 0=no error

OpenDriver opens the device driver specified by name for reading and

writing. It returns the driver's reference number.

driverName is the address of a pascal-style string containing the name of the

refNum is the address of a 16-bit short. Upon return, it will contain the

device driver reference number. This value is used in all subsequent

Returns: an operating system Error Code. It will be one of:

badUnitErr (-21) refNum doesn't match unit table

unitEmptyErr (-22) refNum specifies NIL handle in unit table

openErr (-23) Requested Read/Write permission and the driver's Open

dInstErr (-26) Couldn't find driver in resource file

Notes: While the Sound Driver and Disk Driver open at system startup time, the

rest of the drivers are opened at the specific request of an application.

Before a driver is opened, you refer to it by name. After opening, it is