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Block device drivers respond to this I/O control code in order to service FAT file system requests to read data from the block device.
Parameters
- hDevice
- Handle to the block device.
- dwIoControlCode
- Specifies this code.
- lpInBuffer
- Pointer to an SG_REQstructure..
- nInBufferSize
- Specifies the size of the SG_REQstructure.
- lpOutBuffer
- Not used.
- nOutBufferSize
- Not used.
- lpBytesReturned
- Pointer to a DWORDto receive total bytes returned.
- lpOverlapped
- Not used.
Return Values
When this function returns, the FAT file system expects the sr_statusmember of SG_REQto be set to either ERROR_SUCCESS if the read succeeded, or a standard error return value, otherwise. Certain errors are automatically retried, such as ERROR_BAD_UNIT if the device has been removed and ERROR_NOT_READY if the driver is shutting down or starting up. Block device drivers should return ERROR_GEN_FAILURE for any unknown or unexpected errors.
Remarks
In Windows CE versions prior to 3.0, this code was called DISK_IOCTL_READ. The FAT file system fills in the SG_REQstructure passed to the block device driver as follows:
- sr_start
- Starting block number.
- sr_num_sec
- Number of blocks to read.
- sr_num_sg
- Number of scatter or gather buffers, normally 1.
- sr_callback
- NULL.
- sr_sglist[0].sb_buf
- Pointer to the buffer to read blocks into. This buffer is unaligned.
- sr_sglist[0].sb_len
- Specifies the size of the
sr_sglist[0].sb_bufbuffer, in bytes.
If sr_num_sgis greater than 1, the block device driver should fill in additional entries in the sr_sglistarray.
Requirements
Runs on Versions Defined in Include Link to Windows CE OS 3.0 and later Note This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.
Last updated on Tuesday, July 13, 2004