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.
See Also