HP 3000 Manuals

Accessing Files Programmer's Guide

Topics in this Manual 

When you create a file, you specify certain permanent attributes that the
file will have based upon its intended use.  Chapter 2, "Creating a File"
describes the physical characteristics that are determined when you
create a file and the intrinsics and commands you use to specify those
physical characteristics

What name do you give a file that you create?  How does MPE/iX recognize
your file?  Chapter 3, "Specifying a File Designator" describes how you
designate a file name in your program and discusses file naming
conventions maintained by MPE/iX.

You may classify your file as a new, temporary, or permanent file.
Chapter 4, "Specifying a Domain" discusses these classifications.

Before your program can access or otherwise manipulate a file, the
program must open that file.  Program examples illustrating various ways
you can open a file are described in Chapter 5, "Opening a File."

Once your program is finished accessing or manipulating a file,the file
must be closed.  Program examples illustrating various ways you can close
a file are described in Chapter 6, "Closing a File."

One of the file system's principal concerns is the transfer of
information to and from your files.  Chapter 7, "Record Selection and
Data Transfer" discusses how you can use MPE/iX file system intrinsics to
select records and transfer data between your program and files.

Program examples illustrating various ways to write data from your
program to a file are described in chapter 8, "Writing to a File."

Program examples illustrating various ways to read data from a file are
described in chapter 9, "Reading From a File."

A special method of accessing a file, called update access, is discussed
in chapter 10, "Updating a File."

You can access a file mapped directly through memory loads and stores,
thus bypassing the overhead associated with accessing the file through
file system intrinsics.  Chapter 11, "Accessing a File Using Mapped
Access" describes mapped access of a file and the applications where
mapped access may increase your program's performance.

There are special considerations you must take into account when you are
accessing a file that is being shared concurrently by others.  Chapter 12
,"Sharing a File" discusses file sharing methods available to you.

Associated with each account, group, and individual file, is a set of
security provisions that specifies any restrictions on files in that
account or group, or to that particular file.  These provisions are
discussed in chapter 13, "Maintaining File Security."

MPE/iX provides a number of commands and intrinsics that enable you to
obtain information about your files.  You can use the commands and
intrinsics described in chapter 14, "Getting File Information" for a
variety of purposes.

The HP Pascal/iX program examples found in appendix A, "HP Pascal/XL
Program Examples" are provided to help you better understand how to use
file system intrinsics to perform file access tasks.

MPE/iX 5.0 Documentation