You can write a program with any text editor or word processor.
MPE/iX provides two facilities for entering text that you can use
to create a source file for a program: Editor and Toolset/XL.
For an overview of Editor and Toolset/XL, refer to Chapter 2,
"Utilities and Tools"
Since these facilities can be used for writing
documents, memos, and programs, the output is called text files.
Although the source code for a program is a text file, this guide
refers to it as a source file for program development purposes.
How to Use Intrinsics |
 |
Many programs use low-level, system supplied
procedures or subroutines to handle recurring tasks.
On MPE/iX, these are performed through a set of procedures
called intrinsics, which are an integral part
of the operating system.
Intrinsics are always available to any process on the system and
allow a program to gain access to system services.
Tasks that intrinsics provide include:
Accessing and alteration of files (for example, writing to a file)
Requesting of utility functions (for example, perform ASCII/binary
number conversion)
Access to system resources (for example, obtain system timer
information)
You can manipulate and manage processes and system
resources by means of intrinsics, provided you have the required
execution privileges.
Many intrinsics return values to the caller.
Most do this through parameters; some, through functional returns.
Most intrinsics are coded in HP Pascal/iX (one of
the systems programming languages for the 900 Series HP 3000)
and are defined by a procedure declaration consisting of:
Procedure header, containing the procedure name and type, procedure definitions, and other information about the procedure.
Procedure body, containing executable statements and declarations local to this procedure.
Intrinsics work like user-written procedures, except that the details of performing the task are invisible to you.
|
| |
|
 | NOTE:
Most intrinsics are callable from any language supported on MPE/iX.
|
|
| |
|
The MPE/iX intrinsic mechanism provides flexible and convenient access to
intrinsic routines from various languages.
In some programming languages, you need not (or cannot) give
descriptions for procedures that are external to your program.
When you designate that an external routine is an intrinsic, the
compiler uses the Intrinsic Mechanism to correctly invoke the routine by:
Providing a consistent intrinsic interface
Ensuring proper data type conversion
Generating proper reference parameter addresses
Ensuring that the intrinsic is properly called
Although intrinsics usually refer to system routines,
you can define routines that you want to access as if
they were intrinsics and then place them in new or existing
intrinsic files
and libraries.
You invoke an intrinsic by calling it from within a program.
In HP C/iX, HP Pascal/iX, COBOL II/XL, and HP FORTRAN 77/iX programs,
you explicitly call an intrinsic.
The Intrinsics Mechanism facilitates the declaration of system
intrinsics.
All MPE/iX intrinsics are processed as external procedures by user
programs.
Before you can call an intrinsic from a program, you must declare it
in all languages by using an intrinsic declaration statement.
The format varies depending on the language.
Refer to the appropriate language programming guides for details
on how to call intrinsics.
For detailed information on intrinsics and intrinsic declarations,
refer to MPE/iX Intrinsics Reference Manual (32650-90028).
