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You can trap calls to the transaction handling functions **LOGOUT, COMMIT, and ROLLBACK** without having to attach a file callback to every file.

To do this you use **SYSTEM{PROP:TransactionHook}**.  You set this property to the **address** of a function that has the prototype:

myFUNCTION(SIGNED opCode, LONG state, *FILE file, *LONG stop, *CSTRING FileErrCode, *CSTRING FielErrMsg),LONG

The callback function will be called at least 3 times for each operation.

once at the start of the operation (in this case state = **TRANSTATE:STARTING**),

once for each file in the transaction (in this case state = **TRANSTATE:HAVEFILE**)

once at the end of the operation (in this case state = **TRANSTATE:ENDING**)

the **opCode** parameter can be set to **DriverOp:LOGOUT, DriverOp:COMMIT, or DriverOp:ROLLBACK**

the **file** parameter is assigned to one of the files in the transaction if **state **parameter = **TRANSTATE:HAVEFILE**.

Setting the **stop** parameter to **TRUE** causes the RTL to stop execution of normal transaction handling code after this function exits

Setting **FileErrorCode** and **FileError** parameters sets the values for FILEERRORCODE() and FILEERROR() respectively

The return value is the ERROR() that the operation should set.  This function must return 0 if no error is to be reported.