FS_NEWSIZE
Purpose
Changes a file's logical (EOD) size.
Calling Sequence
int far pascal FS_NEWSIZE(psffsi, psffsd, len, IOflag) struct sffsi far * psffsi; struct sffsd far * psffsd; unsigned long len; unsigned short IOflag;
Where
psffsi is a pointer to the file-system-independent portion of an open file instance.
psffsd is a pointer to the file-system-dependent portion of an open file instance.
len is the desired new length of the file.
| IOflag | indicates information about the operation on the handle. |
|---|---|
| IOflag == 0x0010 | indicates write-through. |
| IOflag == 0x0020 | indicates no-cache. |
Remarks
The FSD should return an error if an attempt is made to write beyond the end with a direct access device handle.
The file system driver attempts to set the size (EOD) of the file to newsize and update sfi_size, if successful. If the new size is larger than the currently allocated size, the file system driver arranges for for efficient access to the newly-allocated storage.
Of the information passed in IOflag, the write-through bit is a mandatory bit in that any data written to the block device must be put out on the medium before the device driver returns. The no-cache bit, on the other hand, is an advisory bit that says whether the data being transferred is worth caching or not.