Accessing a Printer

The command does not wait for the text to be printed, and returns immediately to the program. All printing operations are performed "invisibly" in the background. Obviously, if the printer is not ready, the appropriate requester will appear.

Embedded commands
The text string to be printed can contain embedded commands, and these will be converted into the appropriate control sequences for the current printer automatically. This means that all the effects such as underline, bold, italic and subscript can be included in your programs.

Most embedded commands begin with an "Escape" character, or Chr$(27), and they will work equally well on any printer. Provided that your particular printer has been installed using the Preferences utility, the entire system will be completely transparent. Here are the rules of successful printing:

• Each line of text should be terminated by a single Line Feed. Normally this will be Chr$(10), but an embedded command can also be used like this:

X> LF$=Chr$(27)+"E"
   Printer Send "Greetings" +LF$

• The LF +CR settings found in the AMOS_Interpreter configuration menus are ignored!
• Zeros are printed as normal characters.
• The PRINTER SEND command should not be used to output raw data. Such data may contain embedded commands that can be misinterpreted by the printer device.
• Because PRINTER SEND uses multi--tasking, there may be a slight delay while the text string is being printed.
• If any changes are made to a string while it is being output, the final print-out may become corrupted.
• To avoid unwanted "garbage collection", such an operation can be forced before transmission begins of data to be printed, with a line such as X =Free.

Here is a list of the most useful embedded commands. Note that ESC is simply a standard name for the CHR$(27) character.

Name    Code      Effect
aRIS    ESCc      hard re-set
aRIN    ESC#1     initialise to defaults
aIND    ESCD      true line-feed
aNEL    ESCE      line-feed. This is to be added after every line!
aRI     ESCM      reverse line-feed
aSGRO   ESC[Om    normal character set
aSGR3   ESC[3m    Italics on
aSGR23  ESC[23m   Italics off
aSGR4   ESC[4m    underline on
aSGR24  ESC[24m   underline off
aSGR1   ESC[1m    boldface on