TNS/R Native Application Migration Guide

Introduction to Native Mode

TNS/R Native Application Migration Guide—523745-001

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Shared Run-Time Libraries (SRLs)

There are two types of shared run-time libraries (SRLs): public and private. HP

supplies public SRLs; you cannot create your own. A process can have multiple public

SRLs. You can create your own private SRLs. A process can have only one private

SRL. A private SRL is a native user library. This subsection describes public SRLs. For

details on private SRLs, see Section 6, User Library Migration Tasks.

A shared run-time library (SRL) is in many ways similar to the system library.

An SRL contains code present in virtual memory at run time, to be shared by

processes, rather than linked into object files. Unlike code in the system library, an SRL

can also contain global data, and each process using the SRL automatically gets its

own run-time copy of the data, called instance data. A process can use several SRLs.

The ZTILT process loads the SRLs in each processor at start-up (cold load) from the

active SYSnn subvolume. The SYSnn subvolume, located on $SYSTEM, contains a

version of the operating system image for a particular node. A node can have more

than one SYSnn subvolume, but only one active SYSnn subvolume.

nld resolves references to the SRLs that you have specified when building an

executable program. You must direct nld to search the active SYSnn subvolume for

SRLs. You can also use nld to repeat the resolution process on an existing program to

use a new version of an SRL or let the NonStop Kernel update the references when

you execute the program.

Some of the code configured in the system library for TNS processes is packaged in

SRLs for native processes. For example, the C run-time library, the COBOL85 run-time

library, the TCP/IP sockets library, the Tools.h++ class library, and much of the OSS

API are packaged as SRLs for native processes.

Figure 1-2

on page 1-15, illustrates how code that is bound into TNS C programs or

configured in the system library is packaged in SRLs for native C programs.

Note. Native SRLs are architecturally different from the TNS SRL available to TNS programs

in the OSS environment. As both native SRLs and the TNS SRL are supplied by HP, the

differences do not impact migration. For details on the TNS SRL, see the Binder Manual.