Xerox 721P87491 manual Solution to control-Z and control-D problems

%remove ^D

%remove ^D

%remove ^D

POSTSCRIPT

Solution to control-Z and control-D problems

The recommended solution for the problems induced by control-D and control-Z is to include the following PostScript definitions. They can be loaded permanently, or prepended to jobs that have these problems. These definitions catch illegal uses of these control characters and also allow the legal uses (binary data) to pass through untouched.

(\004) cvn	{} def		%ignore single ^D
character
(\032) cvn	{} def		%ignore single ^Z
character
(\004\004)	cvn	{} def	%ignore ^D^D pattern
(\004\032)	cvn	{} def	%ignore ^D^Z pattern
(\032\004)	cvn	{} def	%ignore ^Z^D pattern
(\032\032)	cvn	{} def	%ignore ^Z^Z pattern
(\004\004\004) cvn {} def			%ignore ^D^D^D pattern
(\004\004\032) cvn {} def			%ignore ^D^D^Z pattern
(\004\032\004) cvn {} def			%ignore ^D^Z^D pattern
(\004\032\032) cvn {} def			%ignore ^D^Z^Z pattern
(\032\004\004) cvn {} def			%ignore ^Z^D^D pattern
(\004\032\004) cvn {} def			%ignore ^D^Z^D pattern
(\032\032\004) cvn {} def			%ignore ^Z^Z^D pattern
(\032\032\032) cvn {} def			%ignore ^Z^Z^Z
pattern

%

%The following code redefines PS operators and names containing control

%characters. Jobs containing the redefined commands will run without

%the undefined error. Additional lines may be added here as needed.

(\004initgraphics) cvn {initgraphics} def

	%remove ^D
(initgraphics\004)		cvn {initgraphics}
def	%remove ^D
(showpage\004) cvn		{showpage}
def		%remove ^D

%Examples of case sensitivity. (sp\004) cvn {sp}

def

(Sp\004) cvn {Sp} def

(SP\004) cvn {SP} def

The preceding definitions use the following rules:

•Isolated illegal characters. If the illegal characters occur alone or only with some combination of other illegal characters, then the resulting token may be redefined as an empty PostScript procedure, as shown in this example:

(\004) cvn {} def

Note: It is not desirable to redefine the token as null because this would leave a null object on the operand stack.

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