PBControlSync

Send control information to the device driver

#include <Devices.h> Device Manager

ParmBlkPtr pb ; address of a 50-byte CntrlParam structure

Boolean async ; 0=await completion; 1=immediate return

returns Error Code; 0=no error

PBControl sends control information from memory to an open device driver

(ioRefNum) on the drive specified by ioVRefNum. The csCode parameter

identifies the type of control information that begins at csParam. Both csCode

and csParam depend on individual drivers for their values.

pb is the address of a 50-byte IOParam structure. The following fields

are relevant:

Out-In Name Type Size Offset Description

-> ioCompletion ProcPtr 4 12 Completion routine address (if async =TRUE)

-> ioRefNum short 2 24 Device reference number

-> csCode short 2 26 Type of information sent

-> csParam Record 22 28 Control or status information for the call

<- ioResult OSErr 2 16 Error Code (0=no error, 1=not done yet)

-> ioVRefNum short 2 22 Drive identification

async is a Boolean value. Use FALSE for normal (synchronous) operation

or TRUE to enqueue the request and resume control immediately. See

Async I/O.

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

noErr (0) No error

controlErr (-17) Driver can't respond to Call

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

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

notOpenErr (-28) Driver not open

Notes: The values passed in csCode and csParam vary, depending on which driver

is being called. To store information in csParam you have to perform the

proper type coercion. csParam is declared as up to 22 bytes because its

actual contents can go up that high and will vary from one Control or Status

call to an other.

Referenced by (2):