VX/SMG - SMG

Description

VX/SMG is a full implementation of DEC’s VMS/OpenVMS Screen Management Service (SMG$) for Linux and Windows. It provides a call-compatible interface for all 3GL languages, allowing applications that use SMG$ routines on VMS to function identically on modern platforms.

VX/SMG ensures that user programs remain independent of the physical display devices, offering virtual displays, pasteboards, viewports, and advanced terminal rendering features.

Key Features

• Full SMG$ API Compatibility – Implements all VMS SMG$ calls without modification.

• Terminal Independence – Works with VT100, VT220, VTxxx ANSI, AT386, and DECterm.

• Advanced Window Management – Supports pasteboards, multiple windows, overlapping views.

• Extended Rendering Features – Includes double-wide characters, scrolling regions, and cursor control.

• Seamless Migration – Works without modifying original VMS SMG applications.

• Performance Optimized – Implements a native C-based terminal driver, bypassing curses, termcap, and terminfo for high-speed execution.

VX/SMG Features and Compatibility

VX/SMG retains all core functionalities of VMS/OpenVMS SMG while enabling enhanced flexibility in modern environments.
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Feature	Description
Virtual Displays	Allows independent screen areas for applications.
Pasteboards	Provides a logical screen buffer that manages multiple displays.
Viewports	Enables scrollable window views into larger virtual displays.
Double-Wide Characters	Supports double-wide and double-high text rendering.
Terminal Independence	Compatible with VT100, VT220, VTxxx, and DECterm.
Cursor & Text Control	Supports positioning, deletion, insertion, and erasure of text.

VX/SMG enables seamless execution of legacy VMS SMG applications while enhancing performance and portability.

VX/SMG Functionality & Terminal Support

Multiple Screen Regions

VX/SMG allows applications to create multiple independent windows using virtual displays, each of which can be dynamically moved, updated, or hidden.

• Pasteboards – Act as logical containers for multiple screen areas.

• Viewports – Provide zoomed-in windows into larger virtual displays.

• Occlusion Checking – Ensures correct layering of overlapping windows.

Direct Terminal Access

VX/SMG does not rely on curses, termcap, or terminfo, instead using a native C-based driver for:

• Faster rendering

• Hardware scrolling support

• More efficient screen updates

Supported terminals include:

✅ VT100, VT220, VTxxx ANSI

✅ AT386 and DECterm

Telnet Image — (TOLAS screen kindly donated by GSI Transcomm)

Windows version of above screen. WINSMG is now obsolete and will only be resurrected under pain of torture, imminent death or cash.

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Example: Using Virtual Displays in VX/SMG

#include "vxsmg.h"

int main() {
    SMG$CREATE_VIRTUAL_DISPLAY(24, 80, &display_id);
    SMG$PASTE_VIRTUAL_DISPLAY(display_id, pasteboard_id, 1, 1, 0);
    SMG$PUT_LINE(display_id, "Welcome to VX/SMG!");
    SMG$DELETE_VIRTUAL_DISPLAY(display_id);
    return 0;
}

VX/SMG API Reference (SMG$ Functions)

VX/SMG fully implements the VMS SMG$ API, ensuring compatibility with existing applications.

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SMG$ API	Function
SMG$ALLOW_ESCAPE	Enables escape sequence handling in terminal input.
SMG$BEGIN_DISPLAY_UPDATE	Locks the display for batch updates.
SMG$BEGIN_PASTEBOARD_UPDATE	Begins an optimized pasteboard update session.
SMG$CANCEL_INPUT	Cancels pending input requests.
SMG$CHANGE_PBD_CHARACTERISTICS	Modifies pasteboard characteristics.
SMG$CHANGE_RENDITION	Changes text appearance (e.g., bold, underline).
SMG$CHANGE_VIEWPORT	Adjusts viewport dimensions.
SMG$CHANGE_VIRTUAL_DISPLAY	Modifies properties of a virtual display.
SMG$CHANGE_VIRTUAL_KEYBOARD	Alters keyboard settings.
SMG$CHECK_FOR_OCCLUSION	Determines if a display is occluded.
SMG$CONTROL_MODE	Configures display control modes.
SMG$COPY_VIRTUAL_DISPLAY	Duplicates a virtual display.
SMG$CREATE_MENU	Creates a menu interface.
SMG$CREATE_PASTEBOARD	Creates a logical screen buffer.
SMG$CREATE_VIEWPORT	Defines a viewport in the display.
SMG$CREATE_VIRTUAL_DISPLAY	Allocates a new virtual screen region.
SMG$CREATE_VIRTUAL_KEYBOARD	Creates a virtual keyboard.
SMG$CURSOR_COLUMN	Gets or sets the cursor column.
SMG$CURSOR_ROW	Gets or sets the cursor row.
SMG$DEFINE_KEY	Assigns a function to a key.
SMG$DELETE_CHARS	Removes characters from the display.
SMG$DELETE_LINE	Deletes a line of text.
SMG$DELETE_MENU	Removes a menu from memory.
SMG$DELETE_PASTEBOARD	Deletes a pasteboard.
SMG$DELETE_VIEWPORT	Removes a viewport from the display.
SMG$DELETE_VIRTUAL_DISPLAY	Removes a virtual display from memory.
SMG$CREATE_VIRTUAL_KEYBOARD	Creates a virtual keyboard.
SMG$CURSOR_COLUMN	Gets or sets the cursor column.
SMG$CURSOR_ROW	Gets or sets the cursor row.
SMG$DEFINE_KEY	Assigns a function to a key.
SMG$DELETE_CHARS	Removes characters from the display.
SMG$DELETE_LINE	Deletes a line of text.
SMG$DELETE_MENU	Removes a menu from memory.
SMG$DELETE_PASTEBOARD	Deletes a pasteboard.
SMG$DELETE_VIEWPORT	Removes a viewport from the display.
SMG$DELETE_VIRTUAL_DISPLAY	Removes a virtual display from memory.
SMG$DELETE_VIRTUAL_KEYBOARD	Removes a virtual keyboard.
SMG$DISABLE_BROADCAST_TRAPPING	Disables broadcast message trapping.
SMG$DRAW_CHAR	Draws a single character at the cursor position.
SMG$DRAW_CHARACTER	Renders a character at a specified position.
SMG$DRAW_LINE	Draws a line on the virtual display.
SMG$DRAW_RECTANGLE	Creates a rectangular shape on the display.
SMG$END_DISPLAY_UPDATE	Unlocks the display after batch updates.
SMG$END_PASTEBOARD_UPDATE	Ends an optimized pasteboard update session.
SMG$ERASE_CHARS	Erases specified characters from the display.
SMG$ERASE_COLUMN	Clears a column of text on the display.
SMG$ERASE_DISPLAY	Clears the entire display.
SMG$ERASE_LINE	Erases the current line from the display.
SMG$ERASE_PASTEBOARD	Clears all content from the pasteboard.
SMG$FIND_CURSOR_DISPLAY	Identifies which display contains the cursor.
SMG$FLUSH_BUFFER	Flushes output buffers to the terminal.
SMG$GET_BROADCAST_MESSAGE	Retrieves system broadcast messages.
SMG$GET_CHAR_AT_PHYSICAL_CURSOR	Gets the character at the cursor position.
SMG$GET_DISPLAY_ATTR	Retrieves display attributes of a virtual screen.
SMG$GET_KEYBOATD_ATTRIBUTES	Gets keyboard characteristics.
SMG$GET_PASTEBOARD_ATTRIBUTES	Retrieves pasteboard properties.
SMG$GET_PASTING_INFO	Fetches details on pasting order.
SMG$GET_TERM_DATA	Retrieves terminal configuration data.
SMG$GET_VIEWPORT_CHAR	Gets the character at viewport position.
SMG$HOME_CURSOR	Moves the cursor to the home position.
SMG$INIT_TERM_TABLE	Initializes the terminal information table.
SMG$INIT_TERM_TABLE_BY_TYPE	Initializes a terminal table by type.
SMG$INSERT_CHARS	Inserts characters at cursor position.
SMG$INSERT_LINE	Inserts a new line at cursor.
SMG$INVALIDATE_DISPLAY	Marks the display as needing refresh.
SMG$KEYCODE_TO_NAME	Converts a keycode to a name.
SMG$KEYPAD_MODE	Sets the keypad mode.
SMG$LABEL_BORDER	Adds a border label to a display.
SMG$LIST_PASTING_ORDER	Lists the pasting order of virtual displays.
SMG$LOAD_VIRTUAL_DISPLAY	Loads a virtual display into memory.
SMG$MOVE_TEXT	Moves text from one location to another.
SMG$MOVE_VIRTUAL_DISPLAY	Moves a virtual display on the screen.
SMG$NAME_TO_KEYCODE	Converts a key name to its keycode.
SMG$PASTE_VIRTUAL_DISPLAY	Adds a virtual display to the pasteboard.
SMG$POP_VIRTUAL_DISPLAY	Removes the topmost virtual display from the stack.
SMG$PRINT_PASTEBOARD	Prints the contents of the pasteboard.
SMG$PUT_CHARS	Writes characters to the virtual display.
SMG$PUT_CHARS_HIGHWIDE	Writes double-height, double-wide characters.
SMG$PUT_CHARS_MULTI	Writes multi-byte character strings.
SMG$PUT_CHARS_WIDE	Writes wide characters to the display.
SMG$PUT_LINE	Outputs a line of text to the display.
SMG$PUT_LINE_HIGHWIDE	Outputs a high-wide formatted line.
SMG$PUT_LINE_WIDE	Outputs a wide-character formatted line.
SMG$PUT_PASTEBOARD	Writes a pasteboard to the screen.
SMG$PUT_WITH_SCROLL	Outputs text with automatic scrolling.
SMG$READ_FROM_DISPLAY	Reads data from a virtual display.
SMG$READ_KEYSTROKE	Reads a keystroke from the input buffer.
SMG$READ_STRING	Reads a string of input from the user.
SMG$REPAINT_LINE	Repaints the specified line on the display.
SMG$REPAINT_SCREEN	Repaints the entire screen.
SMG$REPASTE_VIRTUAL_DISPLAY	Repastes a virtual display to the pasteboard.
SMG$RESTORE_PHYSICAL_SCREEN	Restores a previously saved physical screen.
SMG$RETURN_CURSOR_POS	Returns the current cursor position.
SMG$RING_BELL	Sounds the terminal bell.
SMG$SAVE_PHYSICAL_SCREEN	Saves the current physical screen state.
SMG$SAVE_VIRTUAL_DISPLAY	Saves a virtual display to memory.
SMG$SCROLL_DISPLAY_AREA	Scrolls a specified area of the display.
SMG$SCROLL_VIEWPORT	Scrolls within a viewport.
SMG$SELECT_FROM_MENU	Allows the user to select an item from a menu.
SMG$SET_BROADCAST_TRAPPING	Enables or disables broadcast message trapping.
SMG$SET_CURSOR_ABS	Sets the cursor position to absolute coordinates.
SMG$SET_CURSOR_MODE	Sets the cursor visibility and blink mode.
SMG$SET_CURSOR_REL	Moves the cursor relative to its current position.
SMG$SET_DISPLAY_SCROLL_REGION	Defines a scroll region within the display.
SMG$SET_KEYPAD_MODE	Sets the keypad operating mode.
SMG$SET_PHYSICAL_CURSOR	Sets the physical cursor position.
SMG$SET_TERM_CHARACTERISTICS	Modifies terminal characteristics.
SMG$UNPASTE_VIRTUAL_DISPLAY	Removes a virtual display from the pasteboard.

VX/SMG retains all SMG$ APIs required for seamless execution of legacy VMS applications.

Conclusion

✅ 100% SMG$ API compatibility on Linux & Windows

✅ Full terminal control – pasteboards, virtual displays, viewports

✅ No changes needed – identical execution to OpenVMS SMG

✅ Seamless migration with Sector7’s VX/RT

✅ Supports VT-terminals, DECterm, and ANSI-emulation

✅ Optimized for performance – No reliance on termcap/curses

VX/SMG ensures that OpenVMS SMG-based applications function identically on Linux and Windows while enhancing performance and usability.