FS NEWSIZE: Difference between revisions
Created page with "Changes a file's logical (EOD) size. ==Syntax== FS_NEWSIZE(psffsi, psffsd, len, IOflag) ==Parameters== ;psffsi :is a pointer to the file-system-independent portion of an ..." |
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Changes a file's logical (EOD) size. | {{DISPLAYTITLE:FS_NEWSIZE}} | ||
Changes a file's logical (EOD) size. | |||
==Syntax== | ==Syntax== | ||
FS_NEWSIZE(psffsi, psffsd, len, IOflag) | FS_NEWSIZE(psffsi, psffsd, len, IOflag) | ||
==Parameters== | ==Parameters== | ||
;psffsi :is a pointer to the file-system-independent portion of an open file instance. | ;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. | |||
;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. | |||
;len :is the desired new length of the file. | :IOflag == 0x0010 indicates write-through. | ||
:IOflag == 0x0020 indicates no-cache. | |||
;IOflag :indicates information about the operation on the handle. | |||
==Calling Sequence== | |||
<PRE> | <PRE> | ||
int far pascal FS_NEWSIZE(psffsi, psffsd, len, IOflag) | int far pascal FS_NEWSIZE(psffsi, psffsd, len, IOflag) | ||
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unsigned long len; | unsigned long len; | ||
unsigned short IOflag; | unsigned short IOflag; | ||
</PRE> | |||
==Remarks== | ==Remarks== | ||
The FSD should return an error if an attempt is made to write beyond the end with a direct access device handle. | 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. | 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. | 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. | ||
[[Category:IFS Interfaces]] | [[Category:IFS Interfaces]] | ||
Latest revision as of 03:12, 10 February 2020
Changes a file's logical (EOD) size.
Syntax
FS_NEWSIZE(psffsi, psffsd, len, IOflag)
Parameters
- 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.
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;
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.