TNS/E Native Application Conversion Guide

Introduction to Native Mode

TNS/E Native Application Conversion Guide—529659-003

1-22

Benefits of Native Mode

•

General

Native code often runs significantly faster than TNS interpreted or accelerated

code.

Native object code does not need to be accelerated.

Native processes support more global variables than TNS processes.

Native processes support a default stack of 2 MB (expandable to 32 MB),

which is significantly larger than the 64 KB stack limit for TNS processes.

•

C and C++

The native C and C++ compilers and the eld utility run on the PC as part of

ETK. These native cross compilers generate code that runs on NonStop

systems.

The native Guardian and OSS C run-time library functions provide greater

correspondence and interoperability than the TNS C library functions.

The native Guardian and Open System Services C run-time library provide

much of the X/OPEN UNIX 95 application program interface (API).

The native C++ compiler generates code that is easier to debug than the TNS

C++ preprocessor, Cfront.

•

COBOL

The code space limit for a native COBOL program is 32 MB, compared to

128 KB for a TNS COBOL program.

The data space limit of approximately 60 KB for the sum of all the Working-

Storage Sections and File Sections of a TNS process does not apply to native

COBOL programs. The Working-Storage Section and the Extended-Storage

Section are the same in native COBOL, and there is no distinction between

user data space and user extended space.

Native dynamic-link libraries (DLLs) are consulted automatically.

If a TNS COBOL program calls utility routines, it must put the libraries that

contain those routines (one or more of COBOLLIB, CBL85UTL, and CLULIB)

on search lists (using the compiler directives SEARCH, LIBRARY, and

CONSULT).

For a native COBOL program, search lists are optional. If a program does not

have search lists, or if the compiler cannot find an external reference in the

files on the search lists, the compiler automatically searches the DLLs

ZCOBDLL and ZCREDLL and then the file ECOBEXT (the native equivalent of

COBOLEXT).