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Inside Macintosh: Devices /

Chapter 1 - Device Manager / Device Manager Reference

Device Manager Functions / Controlling and Monitoring Device Drivers

Status

You can use the Status function to obtain status information from a device driver.

pascal OSErr Status(short refNum, short csCode,
                    void *csParamPtr); 

refNum

The driver reference number.

csCode

A driver-dependent code specifying the type of information requested.

csParamPtr

A pointer to a csParam array where the status information will be returned.

DESCRIPTION

The Status function returns information about the device driver specified by the refNum parameter. The value you pass in the csCode parameter and the received information pointed to by the csParamPtr parameter are defined by the driver you are calling. For more information, see the appropriate chapters for the standard device drivers in this book and other books in the Inside Macintosh series.

The Status function is a high-level synchronous version of the low-level PBStatus function. Use the PBStatus function if you need to specify a drive number or if you want the status request to be asynchronous.

Note

The Device Manager interprets a csCode value of 1 as a special case. When the Device Manager receives a status request with a csCode value of 1, it returns a handle to the driver's device control entry.
This type of status request is not passed to the device driver.

SPECIAL CONSIDERATIONS

Do not call the Status function at interrupt time. Synchronous requests at interrupt time may block other pending I/O requests and cause the Device Manager to loop indefinitely while it waits for the device driver to complete the interrupted requests.

RESULT CODES

noErr	0	No error
statusErr	-18	Driver does not respond to this status request
badUnitErr	-21	Driver reference number does not match unit table
unitEmptyErr	-22	Driver reference number specifies a nil handle in unit table
abortErr	-27	Request aborted by KillIO
notOpenErr	-28	Driver not open

SEE ALSO

For information about the low-level function for monitoring device drivers, see the next section, which describes the PBStatus function.