Header Files

Header Files


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Syntax
Category Definitions
Type Definition
Description accessing header information using normal Pick utilities.
Through the OSFI (available on release 7.0 or higher), it is possible to access information about an item such as update stamps, permissions, ownership, and driver-specific data.  The header driver translates this information into a format which looks like a standard Pick item.

Note that access to the header information via this driver is read-only. The only way to modify the header information is through the normal update routines.  This is enabled via the "Y" correlative for Pick files.  With the "y" correlative, the user, pib, and/or timedate may be stamped by appending a "u", "p", and/or "t" to the "y" character.  No other information is currently available for normal items.  Header information updates on non-Pick items depend on the behavior of the remote file system to which those items belong.

Any utility which physically moves the data (like "copy") changes the header information.

The "save" and restore utilities save and restore the header information as well.

Raw Attribute Definitions :

When reading items via the header driver, the items are returned as a dynamic array with the following raw attribute definitions:


#  Description

1  User ID - The Pick user name or the Unix user number in hex of the last user to update this item.

2  Pib - The Pick PIB (in hexadecimal) of the last user to update this item.  This field is undefined for non-Pick drivers.

3  Time/date - A hexadecimal representation of the number of seconds elapsed since 12:00 AM December 31, 1967 and the time the item was last updated.

4  Permissions - A hexadecimal number representing the permissions on the item.  This currently only applies to non-Pick items.

5  GroupID - This is the Group ID (in hexadecimal).  This is currently used only by the Unix driver, but may be used by other drivers in the future.

Other attributes are driver-specific.

Q-Pointer Format :

The format of the header Q-pointer is:
file.name
   001 Q
   002
   003 hdr:filename

'hdr' is the name of the 'hdr' host in the 'dm,hosts,' file.

'filename' is the name of the target file to examine. This may be a local Pick file (assuming the Y correlative has been added to the D-pointer), or a remote file (Unix or Dos).

The file may also be opened by pre-pending the filename with the string "hdr:".
Options
See Also Super-Q-Pointer Open Systems File Interface hosts qs-pointer save copy
Example
Warnings Because the hdr: driver is read-only, it does not make sense to create a "qs" pointer to it (to attempt to save the header data).  Any attempt to do this will have no affect upon a restore.  Note that it is not necessary to save header information since it is implicitly saved and restored using the "save" and restore utilities.

Header information is NOT recorded on a "t-dump" since the succeding "t-load" is considered to be a batch of new updates which change the header information in a driver-specific manner.

Note that updates performed to a file from a remote site will always show the updated user as "dm".
Compatibility D3 7.0
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