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DBAsyncParamBlockRec structure
#include
typedef struct DBAsyncParamBlockRec {Size Offset Description
ProcPtr completionProc; Â4 0 pointer to completion routine
OSErr result; Â2 4 result of call
long userRef; Â4 6 for application's use
long ddevRef; Â4 10 for ddev's use
long reserved; Â4 14 for internal use
}DBAsyncParamBlockRec Â18
typedef DBAsyncParamBlockRec *DBAsyncParmBlkPtr;
The completionProc field is a pointer to a completion routine that the database
extension calls when it has completed executing the asynchronous function.
Before calling the completion routine, the
Data Access Manager places a pointer to the asynchronous parameter
block in the A0 register. If you do not want to use a completion routine, set this
parameter to NIL.
The database extension sets the result field to 1 while the routine is
executing, and places the result code in it when the routine completes. Your
application can poll this field to determine when an asynchronous routine has
completed execution.
The userRef field is reserved for the application's use. Because the
Data Access Manager passes a pointer to the parameter block to the
completion routine, you can use this field to pass information to the completion
routine.
The ddevRef field is reserved for use by the database extension, and the
reserved field is reserved for use by the Data Access Manager.
You can use the DBKill function to cancel an asynchronous routine.
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