IOCTL_USBPRINT_GET_1284_ID

The IOCTL_USBPRINT_GET_1284_ID control code allows upper-layer software (such as a language monitor), to request and obtain the printer's IEEE 1284 device ID string.

To perform this operation, call the DeviceIoControl function (described in the Microsoft Windows SDK documentation) with the following parameters.


bRet = DeviceIoControl(
    (HANDLE)  hDevice, 
 IOCTL_USBPRINT_GET_1284_ID, // dwIoControlCode 
    NULL,   // lpInBuffer
    0,      // nInBufferSize
    (PUCHAR)  lpOutBuffer,
    (DWORD)  nOutBufferSize, 
    (LPDWORD)  lpBytesReturned,
    (LPOVERLAPPED)  lpOverlapped 
  );

Parameters

hDevice

The handle to the print device.

dwIoControlCode

The control code for the operation. This value identifies the specific operation to be performed and the type of device on which to perform it. Use IOCTL_USBPRINT_GET_1284_ID for this operation.

lpInBuffer

Not used in this operation; set this parameter to NULL.

nInBufferSize

Not used in this operation; set this parameter to 0.

lpOutBuffer

A pointer to the output buffer, which will contain UCHAR data. On success this buffer can hold the following: a two-byte prefix that specifies the size, in bytes, of the device's IEEE 1284 device ID; the device ID; and a null terminator. An IEEE 1284 device ID can be up to 64 KB in size. On failure, if GetLastError (described in the Microsoft Windows SDK documentation) returns the error code STATUS_BUFFER_TOO_SMALL, the output buffer was not large enough to hold the data intended for it.

nOutBufferSize

The size, in bytes, of the output buffer, which is pointed to by the lpOutBuffer parameter. The output buffer must be large enough to contain a two-byte quantity holding the length of the device's IEEE 1284 device ID, the device ID (up to 64 KB in size), and a terminating null.

lpBytesReturned

A pointer to a variable that receives the size of the data stored in the lpOutBuffer buffer, in bytes.

If the output buffer is too small to return any data then the call fails, GetLastError returns the error code ERROR_INSUFFICIENT_BUFFER, and the returned byte count is zero.

If lpOverlapped is NULL (nonoverlapped I/O), lpBytesReturned cannot be NULL. If lpOverlapped is not NULL (overlapped I/O), lpBytesReturned can be NULL. If this is an overlapped operation, you can retrieve the number of bytes returned by calling the GetOverlappedResult function. If hDevice is associated with an I/O completion port, you can get the number of bytes returned by calling the GetQueuedCompletionStatus function. GetOverlappedResult and GetQueuedCompletionStatus are described in the Windows SDK documentation.

lpOverlapped

A pointer to an OVERLAPPED structure (described in the Windows SDK documentation).

If hDevice was opened with the FILE_FLAG_OVERLAPPED flag, lpOverlapped must point to a valid OVERLAPPED structure. In this case, DeviceIoControl is performed as an overlapped (asynchronous) operation. If the device was opened with the FILE_FLAG_OVERLAPPED flag and lpOverlapped is NULL, the function fails in unpredictable ways.

If hDevice was opened without specifying the FILE_FLAG_OVERLAPPED flag, lpOverlapped is ignored and the DeviceIoControl function does not return until the operation has been completed, or until an error occurs.

Return Value

If the operation succeeds, DeviceIoControl returns a nonzero value.

If the operation fails, DeviceIoControl returns zero. To get extended error information, call GetLastError.

Headers

Declared in usbprint.h. Include usbprint.h.

 

 

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