Xerox 721P87491 manual Multiple jobs in one input file

POSTSCRIPT

•Illegal characters adjacent to legal characters. If there is no white space character (as defined in the PostScript Language Reference Manual, second edition) between the illegal character or characters and legal PostScript characters, then that combination can be redefined to be the legal PostScript substring only, as shown in these examples:

(showpage\004) cvn {showpage} def (sp\004) cvn {sp} def

Note: It is not desirable to redefine a legal substring ABC as some other legal substring XYZ in the illegal token initialization file. For instance, although showpage frequently is redefined by PostScript code to be sp for brevity, it may seem to make sense to redefine sp <control D> as showpage. However, if the client application creating the PostScript defines sp to mean show rather than showpage, then to have sp <control D> initialized to mean showpage is an error.

Also, due to case sensitivity, some patterns may have to appear with the same case variety as in the PostScript jobs to be processed.

Because there may be an infinite number of character combinations, the system administrator is encouraged to redefine only known or suspect problem tokens.

Multiple jobs in one input file

Note that the above control-D handling does not perform true PostScript job encapsulation. Therefore, the following PostScript job situations may cause problems. All of these problems are due to having multiple PostScript jobs in one input file. If problems occur, break the concatenated masters into separate input files.

•Because control-Ds are not interpreted as end-of-job (EOJ), PostScript virtual memory (VM) is not restored before the next job. This means that the next job environment is not “clean,” which may or may not cause problems. PostScript VM may also run out since VM is not restored by control-D. Note that all Xerox PostScript products do restore VM at the end of their input file, so single PostScript jobs per input file are always handled correctly.

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Some of the PostScript jobs execute exitserver, which stays in effect until EOJ. Because the control-Ds are not interpreted as EOJ, subsequent non-exitserver job definitions become permanent, which could consume all of the PostScript VM or cause other PostScript problems.

A job executes code that flushes the input data up to EOJ. Because the control-D is not interpreted as EOJ, it does not stop the flushing. Therefore, the rest of the PostScript jobs in the input file are ignored.

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