DFHFCL (file control shared resources pool processor)
Call mechanism
BALR, obtaining LIFO storage on entry.
Entry address
DFHFCLNA. DFHFCL is, together with DFHFCN and DFHFCM, link-edited with DFHFCFS. All calls to DFHFCL are made from DFHFCN; the entry point address is known to DFHFCN from the link edit.
Purpose
The shared resources pool processor is part of the file control component.
This program is called at file open time to create a specific local shared resources pool if it does not exist. It is also called to delete a specific pool when the last file to use the pool is being closed.
The size and characteristics of the pool being built are obtained either from information in the resource definition or, if that information has not been provided, from the best information available to DFHFCL at the time of the open.
Called by
DFHFCL is called exclusively by DFHFCN.
Inputs
The FCLPARAM parameter list, created in DFHFCN’s automatic storage and addressed by register 1 on the call.
The input parameters are:
LSR pool number
Outputs
Returned in the FCLPARAM parameter list:
BLDVRP/DLVRP return code
VSAM return code
Operation
If the request is for LSR pool creation, DFHFCL first checks whether the SHRCTL block includes specifications for the number of strings, maximum key length, and the number of virtual and hyperspace buffers of each of the eleven sizes in the pool. If these values are known, DFHFCL sets up the BLDVRP parameter list and creates the pool by issuing the BLDVRP macro.
If some or all of the pool characteristics are not specified in the SHRCTL definition, DFHFCL calculates the pool requirements from the information in the FCT and the VSAM catalog.
Each FCT entry is inspected to find whether it is to be included in the pool being built. If so, its DSNAME is determined and this is used to obtain data set characteristics from the VSAM catalog. The information required for the BLDVRP macro is accumulated in the SHRCTL block and the pool is built from these values.
If the request is for LSR pool deletion, DFHFCL first obtains the VSAM statistics for the pool and saves them in the SHRCTL block. These statistics are unobtainable after the pool has been deleted.
DFHFCL next deletes the specified pool by issuing a DLVRP macro.
Finally, DFHFCL sends pool statistics to the statistics domain as unsolicited data.
How loaded
As a constituent part of DFHFCFS, which is loaded by DFHFCRP as part of file control initialization.