|Document revision date: 30 March 2001
Order Number: AA--PV6LD--TK
This manual documents the screen management routines contained in the SMG$ facility of the OpenVMS Run-Time Library.
Revision/Update Information: This manual supersedes the OpenVMS RTL Screen Management (SMG$) Manual, OpenVMS Alpha Version 7.1 and OpenVMS VAX Version 7.1.
Software Version: OpenVMS Alpha Version 7.3 OpenVMS VAX Version 7.3
Compaq Computer Corporation
© 2001 Compaq Computer Corporation
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Compaq shall not be liable for technical or editorial errors or omissions contained herein. The information in this document is provided "as is" without warranty of any kind and is subject to change without notice. The warranties for Compaq products are set forth in the express limited warranty statements accompanying such products. Nothing herein should be construed as constituting an additional warranty.
The Compaq OpenVMS documentation set is available on CD-ROM.
This manual provides users of the OpenVMS operating system with detailed usage and reference information on screen management routines supplied in the SMG$ facility of the OpenVMS Run-Time Library (RTL).
This manual is intended for system and application programmers who write programs that call SMG$ Run-Time Library routines.
This manual is organized into two parts as follows:
The Run-Time Library routines are documented in a series of reference manuals. A description of how you access the Run-Time Library routines and of OpenVMS features and functionality available through calls to the SMG$ Run-Time Library appears in the OpenVMS Programming Concepts Manual. Descriptions of other RTL facilities and their corresponding routines and usages are discussed in the following books:
The Guide to the POSIX Threads Library contains guidelines and reference information for Compaq POSIX Threads2, the Compaq Multithreading Run-Time Library.
The OpenVMS Command Definition, Librarian, and Message Utilities Manual provides information useful for writing applications that use line composition with keypad keys.
The OpenVMS I/O User's Reference Manual contains information about using mailboxes.
Application programmers using any programming language can refer to the Guide to Creating OpenVMS Modular Procedures for writing modular and reentrant code.
High-level language programmers will find additional information on calling Run-Time Library routines in their language reference manual. You can also find additional information in the language user's guide provided with your OpenVMS language software.
For a complete list and description of the manuals in the OpenVMS documentation set, see the OpenVMS Version 7.3 New Features and Documentation Overview Manual.
For additional information about OpenVMS products and services, access the Compaq website at the following location:
1 This manual has been archived but is available on the OpenVMS Documentation CD-ROM.
2 Compaq POSIX Threads was formerly called DECthreads.
Compaq welcomes your comments on this manual. Please send comments to either of the following addresses:
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The following conventions are used in this manual:
|A sequence such as Ctrl/ x indicates that you must hold down the key labeled Ctrl while you press another key or a pointing device button.
|A sequence such as PF1 x x indicates that you must first press and release the key labeled PF1 and then press and release another key or a pointing device button.
In examples, a key name enclosed in a box indicates that you press a
key on the keyboard. (In text, a key name is not enclosed in a box.)
In the HTML version of this document, this convention appears as brackets, rather than a box.
A horizontal ellipsis in examples indicates one of the following
|A vertical ellipsis indicates the omission of items from a code example or command format; the items are omitted because they are not important to the topic being discussed.
|In command format descriptions, parentheses indicate that you must enclose choices in parentheses if you specify more than one.
|In command format descriptions, brackets indicate optional choices. You can choose one or more items or no items. Do not type the brackets on the command line. However, you must include the brackets in the syntax for OpenVMS directory specifications and for a substring specification in an assignment statement.
|In command format descriptions, braces indicate required choices; you must choose at least one of the items listed. Do not type the braces on the command line.
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|Italic text indicates important information, complete titles of manuals, or variables. Variables include information that varies in system output (Internal error number), in command lines (/PRODUCER= name), and in command parameters in text (where dd represents the predefined code for the device type).
|Uppercase text indicates a command, the name of a routine, the name of a file, or the abbreviation for a system privilege.
Monospace type indicates code examples and interactive screen displays.
In the C programming language, monospace type in text identifies the following elements: keywords, the names of independently compiled external functions and files, syntax summaries, and references to variables or identifiers introduced in an example.
|A hyphen at the end of a command format description, command line, or code line indicates that the command or statement continues on the following line.
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This manual discusses the Run-Time Library routines that perform terminal-independent functions. The most important aspect of the Screen Management Facility is that user programs are entirely separate from the physical devices that actually perform input and output. Instead of writing directly to a physical screen, the user program writes to a virtual display. Similarly, instead of entering input directly from a physical keyboard, user programs enter input from a virtual keyboard. (Virtual displays and virtual keyboards are logical entities whose usage is described more fully in the following sections.) This separation of virtual operations from physical operations is what allows input/output to be terminal independent.
The SMG$ routines listed below help you design, compose, and keep track of complex images on a video screen. These routines are meant for the types of operations you would normally perform on a VT100-class terminal; they also provide software emulation of screen management functions on terminals that do not have these functions implemented in their hardware. While you can use these routines with video terminals, you can also use them with hardcopy devices and files. The following lists contain all the screen management routines grouped according to their functions.
Table 1-1 lists routines that support third-party terminals; Chapter 5 discusses these routines.
Table 1-2 lists the SMG$ input routines; Chapter 3 discusses these routines.
Table 1-3 lists the SMG$ output routines; Chapter 2 discusses these routines.
The Screen Management Facility provides two important services:
The Screen Management Facility assumes that it has complete control of the terminal. Applications should not mix calls to SMG$ with calls to other screen products such as Compaq GKS or Compaq FMS.
The following sections discuss the fundamental elements of screen management. These elements are the pasteboard, the virtual display, the viewport, and the virtual keyboard.
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