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DAT_PRMRY - Set or enquire primary/secondary locator status

Description:
The routine may be used to promote a locator to become a "primary" locator, to demote it to become a "secondary" locator, or to enquire about the primary/secondary status of a locator. It allows control over the duration for which an HDS container file remains open; each file remains open only so long as there is at least one primary locator associated with it.

Invocation:
CALL DAT_PRMRY( SET, LOC, PRMRY, STATUS )

Arguments:
SET = LOGICAL (Given)
If a .TRUE. value is given for this argument, then the routine will perform a "set" operation to set the primary/secondary status of a locator. Otherwise it will perform an "enquire" operation to return the value of this status without changing it.
LOC = CHARACTER * ( DAT__SZLOC ) (Given and Returned)
The locator whose primary/secondary status is to be set or enquired.
PRMRY = LOGICAL (Given and Returned)
If SET is .TRUE., then this is an input argument and specifies the new value to be set (.TRUE. for a primary locator, .FALSE. for a secondary locator). If SET is .FALSE., then this is an output argument and will return a value indicating whether or not a primary locator was supplied.
STATUS = INTEGER (Given and Returned)
The global status.

Notes:
  • The value of the LOC argument will not normally be changed. However, if it is the last primary locator associated with a container file, and is being demoted from a primary to a secondary locator, then the container file will be left without an associated primary locator. In this case, the locator supplied will be annulled (along with any other secondary locators associated with the same file), a value of DAT__NOLOC will be returned, and the file will be closed.
  • The DAT__NOLOC constant is defined in the include file DAT_PAR.



next up previous
Next: DAT_PUT - Write primitive
Up: ROUTINE DESCRIPTIONS
Previous: DAT_PRIM - Enquire object primitive

HDS Hierarchical Data System
Starlink User Note 92
R.F. Warren-Smith & M.D. Lawden
23rd February 1999
E-mail:rfws@star.rl.ac.uk

Copyright (C) 1999 Central Laboratory of the Research Councils