GetTapePosition

The GetTapePosition function retrieves the current address of the tape, in logical or absolute blocks. 

DWORD GetTapePosition(
  HANDLE hDevice,          // handle of open device
  DWORD dwPositionType,    // type of address to obtain
  LPDWORD lpdwPartition,   // address of current tape partition
  LPDWORD lpdwOffsetLow,   // address of low-order 32 bits of tape 
                           // position
  LPDWORD lpdwOffsetHigh   // address of high-order 32 bits of tape 
                           // position
);

Parameters

hDevice
Identifies the device on which to get the tape position. This handle is created by using CreateFile.
dwPositionType
Specifies the type of address to obtain. This parameter can be one of the following values:
Value Description
TAPE_ABSOLUTE_POSITION The lpdwOffsetLow and lpdwOffsetHigh parameters receive the device-specific block address. The dwPartition parameter receives zero.
TAPE_LOGICAL_POSITION The lpdwOffsetLow and lpdwOffsetHigh parameters receive the logical block address. The dwPartition parameter receives the logical tape partition.

lpdwPartition
Points to a variable that receives the number of the current tape partition. Partitions are numbered logically from 1 through n, where 1 is the first partition on the tape and n is the last. When a device-specific block address is retrieved, or if the device supports only one partition, this parameter receives zero.
lpdwOffsetLow
Points to a variable that receives the low-order 32 bits of the current tape position.
lpdwOffsetHigh
Points to a variable that receives the high-order 32 bits of the current tape position. This parameter can be NULL if the high-order 32 bits are not required.

Return Values

If the function succeeds, the return value is NO_ERROR.

If the function fails, the return value is one of the following error codes:

Error code Description
ERROR_BEGINNING_OF_MEDIA An attempt to access data before the beginning-of-medium marker failed.
ERROR_BUS_RESET A reset condition was detected on the bus.
ERROR_END_OF_MEDIA The end-of-tape marker was reached during an operation.
ERROR_FILEMARK_DETECTED A filemark was reached during an operation.
ERROR_SETMARK_DETECTED A setmark was reached during an operation.
ERROR_NO_DATA_DETECTED The end-of-data marker was reached during an operation.
ERROR_PARTITION_FAILURE The tape could not be partitioned.
ERROR_INVALID_BLOCK_LENGTH The block size is incorrect on a new tape in a multivolume partition.
ERROR_DEVICE_NOT_PARTITIONED The partition information could not be found when a tape was being loaded.
ERROR_MEDIA_CHANGED The tape that was in the drive has been replaced or removed.
ERROR_NO_MEDIA_IN_DRIVE There is no media in the drive.
ERROR_NOT_SUPPORTED The tape driver does not support a requested function.
ERROR_UNABLE_TO_LOCK_MEDIA An attempt to lock the ejection mechanism failed.
ERROR_UNABLE_TO_UNLOAD_MEDIA An attempt to unload the tape failed.
ERROR_WRITE_PROTECT The media is write protected.

Remarks

A logical block address is relative to a partition. The first logical block address on each partition is zero.

Call the GetTapeParameters function to obtain information about the status, capabilities, and capacities of tape drives and media.

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Unsupported.
  Windows CE: Unsupported.
  Header: Declared in winbase.h.
  Import Library: Use kernel32.lib.

See Also

Tape Backup Overview, Tape Backup Functions, CreateFile, GetTapeParameters, SetTapePosition