Apple LaserWriter Select 310 Printer - Manual (Page 51)

C H A P T E R 2
LaserWriter Select 310 Software
PostScript Language Changes 39
printererror 2
PostScript Language Changes 2
Several additions have been made to the PostScript language, which is used by the
LaserWriter Select 310 printer , and by certain other PostScript printers. The additions are
upwardly compatible and do not affect the function of any existing PostScript language
programs.
Note
PostScript language programs that are intended to be compatible with all
PostScript printers should not use the new features. The program can
determine whether or not the new features are present, and it can invoke
them conditionally.
◆
The new features described in the following sections include:
■ packed arrays, which provide a means of cutting down on the amount of virtual
memory allocated for the storage of executable arrays
■ immediately evaluated name, a new kind of name token, that causes names in
procedures to become tightly bound to their values
■ a different kind of operation for the font cache
■ a new general sampling and halftoning technique that allows a larger class of sampled
images to be transferred from a binary source image to the raster output device
■ a different method of handling end-of-line recognition
This section also lists the new operators used in the LaserWriter Select 310 printer.
Syntax status tries printererror –
Definition This procedure is called during execution of showpage or copypage if
the printer mechanism reports an error such as out of paper, no paper
tray, paper jam, cover open, and so on.
status is an integer that encodes details of the error condition. It is device
dependent and is not documented in this developer note.
tries is the number of times printererror has previously been called
during the same showpage or copypage. If printererror returns,
the printed operation is retried. If it aborts, by executing stop, the
printing operation is abandoned.
Standard procedure: printererror interprets status and generates a
PrinterError status message. It then returns, allowing printer errors to be
retried indefinitely.
Error stackoverflow