Guardian Procedure Calls Reference Manual

Table 17 FILE_CREATELIST_ Item Codes (continued)
DescriptionSize
(Bytes)
Item
Code
File format. File format can be 0, 1, or 2. Format 1 files allow only as many as 4 KB blocks and
as many as 2 GB partitions. format 2 files allow larger blocks and partitions. The value 0 (the
default) specifies that the system select the format based on the values of other parameters.
2195
Logical record length (32-bit). For structured disk files, the maximum number of bytes in a logical
record. If omitted, 80 is used. This item is an alternate form for item 43.
4196
Block length (32-bit). For structured files, the size of a block of records. For unstructured files, the
unstructured buffer size. Currently, the maximum supported value, which is also the default value,
is 4096. This item is an alternate form for item 44.
4197
Key offset (32-bit). For key-sequenced disk files, the byte offset from the beginning of the record to
the primary key field. This item is an alternate form for item 45; one of the two items is required for
key-sequenced files.
4198
Primary extent size (32-bit). The size in pages (2048-byte units) of the first extent. If omitted or 0,
a size of 1 is used. The value can be rounded during creation to a multiple of the block size. This
item is an alternate form for item 50.
4199
Secondary extent size (32-bit). The size in pages (2048-byte units) of extents after the first extent.
If 0 or omitted, the size of the primary extent is used. The value can be rounded during creation to
a multiple of the block size. This is an alternate form for item 51.
4200
Block checksumming option. For format 2 structured files, specifies whether data protection needs
to be used through checksum calculation and comparison (1 specified if needed, and 0 if not
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needed). If omitted or -1 is specified, the default value 1 is used. This item is ignored for files that
do not support a checksum option.
Partition maximum extents array. An array of INT values that specify the maximum extents for each
secondary partition. This item is optional and can only be specified for key-sequenced files. If
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present, it must be supplied at some point after item 90 (number of partitions) and item 41 (file
type). If this item is not present, FILE_CREATELIST_ will use the maximum extents value for the file
(item 52) and apply it to each secondary partition. The length of the item is 2 times the number of
partitions (item 90).
Considerations
• Using item-list
In general, if you supply an item in item-list that is not applicable (for example, if you
supply a logical record length for an unstructured file), FILE_CREATELIST_ ignores the item as
long as it passes syntax and value range tests. Exceptions to this are noted in Table 17 above.
• File pointer action
The end-of-file pointer is set to 0 after the file is created.
• Disk allocation with FILE_CREATELIST_
Execution of the FILE_CREATELIST_ procedure does not allocate any disk area; it only provides
an entry in the volume's directory, indicating that the file exists.
• Altering file security
The file is created with the caller's process file security, which can be examined and set with
the PROCESSFILESECURITY procedure. Once a file has been created, its file security can be
altered by opening the file and issuing the appropriate SETMODE and SETMODENOWAIT
procedure calls.
• Odd unstructured files
An odd unstructured file permits reading and writing of odd byte counts and positioning to
odd byte addresses.
400 Guardian Procedure Calls (F)