GETSTOR request

To create a memory object, use the IARV64 GETSTOR request. When you create a memory object, request a size large enough to meet long-term needs; the system, however, abends a program that unconditionally tries to obtain more storage above the bar than the MEMLIMIT allows. IBM® recommends that you specify COND=YES on the request to avoid the abend. In this case, if the request exceeds the MEMLIMIT, the system rejects the request, but the program continues to run. The IARV64 service returns to the caller with a non-zero return code. The recovery routine would be similar to one that would respond to unsuccessful STORAGE macro conditional requests for storage.

The SEGMENTS parameter specifies the size, in megabytes, of the memory object you are creating. The system returns the address of the memory object in the ORIGIN parameter.

Parameters for GETSTOR include:

FPROT=YES gives it fetch protection.
KEY=key specifies its storage key (authorized programs only).
TTOKEN=ttoken indicates what task is to own the memory object.
ALETVALUE=alet identifies the address space in which the memory object is to reside, either the home or primary address space (authorized users only).
USERTKN=user token is an 8-byte token that relates two or more memory objects to each other. Later, the program can request a list of memory objects that have that same token and can delete them as a group.
SVCDUMPRGN=YES specifies that the storage in the memory object is to be included when an SVC dump is requested through SDUMPX SDATA=(RGN). SVCDUMPRGN=NO specifies that the virtual storage in the memory object is not to be included when an SVC dump is requested through SDUMPX SDATA=(RGN). There are other ways to include this storage in the dump, such as the SDUMPX SUMLIST64 or SDUMPX LIST64 requests.
CONTROL=AUTH prevents a memory object from being freed by an unauthorized program (authorized users only). Additionally, CONTROL=AUTH is required if you plan to fix and unfix pages.

When a program creates a memory object, it can specify, through the GUARDSIZE and GUARDHIGH and GUARDLOW parameters, that the memory object is to consist of two different areas. One area is called a guard area; this storage is not accessible; the other area is called the usable area. A later request can change the guard area into a usable area. The section Creating guard areas and changing their sizes can help you understand the important purposes for this kind of memory object.

Before issuing IARV64, issue SYSSTATE ARCHLVL=2 so that the macro generates the correct parameter addresses.