TACL Reference Manual

The TACL Environment
HP NonStop TACL Reference Manual—429513-018
6-12
Avoiding Naming Conflicts With TACL
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Provides for read-only sharing of variables among TACL users
•
Removes the need for loading each library of variables before each use
•
Removes the need for predicting the maximum segment file size a given TACL
user will require
Other application products (that are part of a software RVU) can also create
directories. TACL requires you to specify where to put the associated variables or, by
default, stores them in your current home directory. (To store variables in your home
directory, your home directory must be writable.) The documentation for each product
explains how to access and use these files.
Avoiding Naming Conflicts With TACL
All temporary variables created by TACL begin with colon-circumflex (:^). TACL stores
these variables in the root directory, which is always writable, and guarantees that
these temporary variables will never conflict with any of your own variables.
The TACLINIT file creates a directory called :UTILS_GLOBALS in the default segment
file; each product that needs global, writable variables creates its own directory and
variables within the :UTILS_GLOBALS directory. Such variables are named
:UTILS_GLOBALS: product: var-name.
All TACL variables included with an application product (that is part of a software
RVU), and intended solely for use by that product, are put into subordinate directories
in the directory of the product; the name of each variable of this type begins with a
circumflex (^). This convention allows you to list the directory of a product without
memorizing the names of private utilities.
To avoid conflicts with TACL and application products using TACL, adhere to these
rules:
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Do not create variables whose names begin with a circumflex (^) and never use, in
any way, such variables.
•
Do not create or use variables whose names begin with an underscore (_), except
where specifically permitted as a feature of an application program.
•
Do not create any variables under :UTILS.
•
Do not create any variables under :UTILS_GLOBALS, except where specifically
permitted as a feature of an application program.
•
Do not push or pop :UTILS or :UTILS_GLOBALS.
•
If you modify the use list, ensure that your use list always includes certain
directories necessary for the correct operation of the application program. The
USE command automatically does this for you. The list of necessary directories
depends on the application software version and must not be hard coded in your
TACL programs.