Guardian Procedure Calls Reference Manual

record-specifier
input
INT(32):value
is the four-byte value that specifies the new setting for the current-record and next-record pointers.
record-specifier is a four-byte record-num.Relative Files
-2D specifies that the next write occur at an unused record position.
-1D specifies that subsequent writes be appended to the end-of-file
location.
record-specifier is a four-byte relative-byte-addr.Unstructured Files
-1D or -2D specifies that subsequent writes be appended to the
EOF location.
(For relative and unstructured files, the -1D and -2D remain in effect until a new
record-specifier is supplied.)
The record-specifier is a four-byte record-addr (the primary key), whose format
depends upon the file's block size as follows
Entry-Sequenced Files
Number of bits for the relative record
number within that block
Number of bits for block
number
Block size
12204096
11212048
10221024
923512
Condition Code Settings
indicates that an error occurred (call FILE_GETINFO_ or FILEINFO).< (CCL)
indicates that the POSITION was successful.= (CCE)
indicates no operation; filenum does not designate a disk file.> (CCG )
Considerations
• POSITION does not cause the disk heads to be repositioned (at least until a subsequent data
transfer is initiated).
• POSITION cannot be used with Enscribe format 2 and OSS files if the file was opened with
the "Use 64 bit keys" choice to FILE_OPEN_ (which is necessary to access a file with a file
size of over 2 GB). If an attempt is made to use the POSITION procedure with such files, error
581 is returned. For information on how to perform the equivalent task with Enscribe format
2 files and OSS files greater than approximately 2 gigabytes, see the FILE_SETPOSITION_
Procedure (page 514) .
• Unstructured files
File pointers after POSITION
After a successful call to POSITION for an unstructured file, the file pointers are:
◦
current^record^pointer := record-specifier; next^record^pointer := record-specifier;
◦ Value of record-specifier for unstructured files
Unless the unstructured file is created with the odd unstructured attribute (also known as
ODDUNSTR) set, the RBA passed in record-specifier must be an even number. If the odd
unstructured attribute is set when the file is created, the RBA passed in record-specifier
976 Guardian Procedure Calls (P)