SetTapePosition

The SetTapePosition sets the tape position on the specified device. 

DWORD SetTapePosition(
  HANDLE hDevice,          // handle of open device
  DWORD dwPositionMethod,  // type of positioning to perform
  DWORD dwPartition,       // new tape partition
  DWORD dwOffsetLow,       // low-order 32 bits of tape position
  DWORD dwOffsetHigh,      // high-order 32 bits of tape position
  BOOL bImmediate          // return after operation begins
);

Parameters

hDevice
Identifies the device on which to set the tape position. This handle is created by using the CreateFile function.
dwPositionMethod
Specifies the type of positioning to perform. This parameter must be one of the following values:
Value Meaning
TAPE_ABSOLUTE_BLOCK Moves the tape to the device-specific block address specified by the dwOffsetLow and dwOffsetHigh parameters. The dwPartition parameter is ignored.
TAPE_LOGICAL_BLOCK Moves the tape to the block address specified by dwOffsetLow and dwOffsetHigh in the partition specified by dwPartition.
TAPE_REWIND Moves the tape to the beginning of the current partition. The dwPartition, dwOffsetLow, and dwOffsetHigh parameters are ignored.
TAPE_SPACE_END_OF_DATA Moves the tape to the end of the data on the partition specified by dwPartition.
TAPE_SPACE_FILEMARKS Moves the tape forward (or backward) the number of filemarks specified by dwOffsetLow and dwOffsetHigh in the current partition. The dwPartition parameter is ignored.
TAPE_SPACE_RELATIVE_BLOCKS Moves the tape forward (or backward) the number of blocks specified by dwOffsetLow and dwOffsetHigh in the current partition. The dwPartition parameter is ignored.
TAPE_SPACE_SEQUENTIAL_FMKS Moves the tape forward (or backward) to the first occurrence of n filemarks in the current partition, where n is the number specified by dwOffsetLow and dwOffsetHigh. The dwPartition parameter is ignored.
TAPE_SPACE_SEQUENTIAL_SMKS Moves the tape forward (or backward) to the first occurrence of n setmarks in the current partition, where n is the number specified by dwOffsetLow and dwOffsetHigh. The dwPartition parameter is ignored.
TAPE_SPACE_SETMARKS Moves the tape forward (or backward) the number of setmarks specified by dwOffsetLow and dwOffsetHigh in the current partition. The dwPartition parameter is ignored.

dwPartition
Specifies the partition to position within. If dwPartition is zero, the current partition is used. Partitions are numbered logically from 1 through n, where 1 is the first partition on the tape and n is the last.
dwOffsetLow
Specifies the low-order 32 bits of the block address or count for the position operation specified by the dwPositionMethod parameter.
dwOffsetHigh
Specifies the high-order 32 bits of the block address or count for the position operation specified by the dwPositionMethod parameter. If the high-order 32 bits are not required, this parameter should be zero.
bImmediate
Indicates whether to return as soon as the move operation begins. If this parameter is TRUE, the function returns immediately; if FALSE, the function does not return until the move operation has been completed.

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 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

If the offset specified by dwOffsetLow and dwOffsetHigh specifies the number of blocks, filemarks, or setmarks to move, a positive offset moves the tape forward to the end of the last block, filemark, or setmark. A negative offset moves the tape backward to the beginning of the last block, filemark, or setmark. If the offset is zero, the tape does not move.

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

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, GetTapePosition