Terminal Output

TERM Command

The TERM command allows a user to query or establish certain characteristics of the terminal. When used from the shell as an interactive command:

TERM

the command displays the terminal characteristics. The terminal “type” can also be set from the command line, for example,

TERM VT220

sets the terminal to have the characteristics of a DEC VT220.

The characteristics of the terminal are usually set from a program, however, where the command format is

TERM swidth,sdepth,,,,,pwidth,pdepth,termtype 

where:

• swidth and sdepth are the screen width (in characters) and depth (in lines)

• pwidth and pdepth are the printer width and depth (also in characters and lines, respectively)

• termtype is the terminal type identifier and can appear anywhere in the command as a non-numeric argument

The TERM command also supports single character terminal names which are synonyms for other terminal names. For example,

TERM W

selects the Wyse 60 terminal. To list the supported terminals and their single character synonym (if any), use the CHOOSE.TERM command.

The CHOOSE.TERM Command

The CHOOSE.TERM command allows you to see what terminals are supported on your system and then allows you to select a terminal type by entering a number, the name, or the short name. For example,

USER:CHOOSE.TERM

Terminal Description                   Term Name            Short Name

--------------------                   ---------            ----------

1)   ansi/pc-term compatible with co   ANSI

2)   AT&T 605 80 column 102key keybo   ATT605               Z

3)   cache terminal based on vt220     CACHE

4)   Hazeltine Esprit I,               ESPRIT               E

...
...
...

31)  xterm terminal emulator (X Wind   XTERM

Choose number, term name or short name :

The Short Name field is where the terminal definition has a “termtype=Xentry” and so allows the terminal to be selected via the TERM command using a single character synonym.

The SYSTEM() Function

The MVBasic SYSTEM () function is used to return a limited set of information about the terminal in use. The format is

SYSTEM(code)

where code is an integer that specifies the information desired. The following code values are used for terminal information:

• 1: return a non-zero value if output is not directed to a terminal

• 2: returns the screen width

• 3: returns the screen depth

• 7: returns the type name of this terminal

The @() Function

MultiValue Basic provides terminal output independence using the @ function call, as follows:

• @(m,n) where m is a positive integer

  Moves the cursor to column m and row n, where @(0,0) is the top left hand side of a terminal.

• @(m) where m is a positive integer

  Moves the cursor to column m on the current row.

• @(m) where m is negative integer

  Generates video effect character strings. The value of m and the effect intended are emulation dependent and given by the table below.

• @(m,n) where m is a negative integer

  The same as @(m), except some video effects take an optional argument n, as shown by (nn) in the table below.

Predefined Names

The table below shows all the values we use from a terminfo definition. Caché does not use them all; it only use the ones necessary to support MultiValue Basic. In this table, there are some Caché defined names. These are shown by the name starting with an 'x' and the word "NEW" in the description field.

In the table below, the @(-nn) values vary between emulation. The values shown are for Cache Ideal (aka UniVerse) emulation, unless otherwise noted. The expression 'video attributes' refer to effects such as bold, dim, reverse and so on.

jBASE- And Reality-specific Codes

Values -128 through -191 are for Reality video effects and are a bit map of video effects as shown in the list below. Caché supports these values for ALL emulations as there is no conflict. These values are additive. The only values Caché supports are:

• 0x01 – Half intensity

• 0x02 – Blink

• 0x04 – Reverse

• 0x08 – Blanked

• 0x10 – Underscore

• 0x20 – Bold

• 0x40 – (not defined)

• 0x80 – Always 1

MVBASE-Specific Codes

The color sequences @(-57) through @(-64) are used in the MVBASE emulation to produce dimmed foreground colors. The dimmed colors are white, yellow, magenta, red, cyan, green, blue, and black, respectively.