EVT_SERCX2_PIO_TRANSMIT_INITIALIZE_TRANSACTION callback function (sercx.h)

Article
10/21/2021

The EvtSerCx2PioTransmitInitializeTransaction event callback function is called by version 2 of the serial framework extension (SerCx2) to prepare the serial controller driver to perform a PIO-transmit transaction.

Syntax

EVT_SERCX2_PIO_TRANSMIT_INITIALIZE_TRANSACTION EvtSercx2PioTransmitInitializeTransaction;

void EvtSercx2PioTransmitInitializeTransaction(
  [in] SERCX2PIOTRANSMIT PioTransmit,
  [in] ULONG Length
)
{...}

Parameters

[in] PioTransmit

A SERCX2PIOTRANSMIT handle to a PIO-transmit object. The serial controller driver previously called the SerCx2PioTransmitCreate method to create this object.

[in] Length

The number of bytes to be transferred in the PIO-transmit transaction.

Return value

None

Remarks

Your serial controller driver can, as an option, implement this function. If implemented, the driver registers the function in the SerCx2PioTransmitCreate call that creates the PIO-transmit object.

Your driver should implement an EvtSerCx2PioTransmitInitializeTransaction function if it needs to initialize the serial controller and associated hardware in preparation for a new PIO-transmit transaction. SerCx2 calls this function, if it is implemented, before a PIO-transmit transaction starts. In response to this call, the serial controller driver must call the SerCx2PioTransmitInitializeTransactionComplete method to notify SerCx2 after the initialization is finished.

For more information, see SerCx2 PIO-Transmit Transactions.

Examples

To define an EvtSerCx2PioTransmitInitializeTransaction callback function, you must first provide a function declaration that identifies the type of callback function you're defining. Windows provides a set of callback function types for drivers. Declaring a function using the callback function types helps Code Analysis for Drivers, Static Driver Verifier (SDV), and other verification tools find errors, and it's a requirement for writing drivers for the Windows operating system.

For example, to define an EvtSerCx2PioTransmitInitializeTransaction callback function that is named MyPioTransmitInitializeTransaction, use the EVT_SERCX2_PIO_TRANSMIT_INITIALIZE_TRANSACTION function type, as shown in this code example:

EVT_SERCX2_PIO_TRANSMIT_INITIALIZE_TRANSACTION  MyPioTransmitInitializeTransaction;

Then, implement your callback function as follows:

_Use_decl_annotations_
VOID
  MyPioTransmitInitializeTransaction(
    SERCX2PIOTRANSMIT  PioTransmit,
    ULONG  Length
    )
  {...}

The EVT_SERCX2_PIO_TRANSMIT_INITIALIZE_TRANSACTION function type is defined in the Sercx.h header file. To more accurately identify errors when you run the code analysis tools, be sure to add the Use_decl_annotations annotation to your function definition. The Use_decl_annotations annotation ensures that the annotations that are applied to the EVT_SERCX2_PIO_TRANSMIT_INITIALIZE_TRANSACTION function type in the header file are used. For more information about the requirements for function declarations, see Declaring Functions by Using Function Role Types for KMDF Drivers. For more information about Use_decl_annotations, see Annotating Function Behavior.

Requirements

Requirement	Value
Minimum supported client	Available starting with Windows 8.1.
Target Platform	Desktop
Header	sercx.h
IRQL	Called at IRQL <= DISPATCH_LEVEL.