GetTapePosition info  Overview  Group

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.

See Also

CreateFile, GetTapeParameters, SetTapePosition