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man pages section 4: Device and Network Interfaces

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Updated: Thursday, June 13, 2019

Display (4)


Display - display a document


[file] Display(in mediaType contents
[in title docName]);


Document and Media Exchange Message Sets                            Display(4)

       Display - display a document

       [file] Display(in mediaType contents
                      [in title docName]);

       The Display request causes the handler to display (present or manifest)
       a document to the user.  For example,  an  audio  manipulation  utility
       would be said to ``display'' audio documents when it plays them.

       The handler must decide issues such as:

          o  When the display operation can be deemed completed

          o  What user gesture signals the completion of the display

          o  What the handling tool should do with itself after replying

       The  contents  argument is the contents of the document.  If this argu-
       ment is unset (in other words, has a value of (char *)0), then the con-
       tents  of  the  document  are  in  the file named in the message's file
       attribute.  The data type (mediaType) of the contents  argument  should
       be  string,  unless  nulls  are valid in the given media type, in which
       case the data type must be bytes.

       The docName argument contains the name of the document.  If the docName
       argument is absent and the file attribute is set, the file name is con-
       sidered to be the title of the document.  This string would be suitable
       for display in a window title bar, for example.

       The  ttmedia_ptype_declare(3) function can be used to register for, and
       help process, this message.

       This message can be sent with the ttmedia_load(3) function.

       When the document to be displayed is read-only or unlikely to be  modi-
       fied  the  Display  message is frequently used instead of the Edit mes-

       To display a PostScript document, the application can  send  a  Display
       request  with  a  first  argument  whose vtype is PostScript, and whose
       value is a vector of bytes such as:

            %!\n/inch {72 mul} def...

       The \n in the example represents the newline character.

       To display a PostScript document contained in a file,  the  application
       can send a Display request with the file attribute set to that file and
       with an unset first argument whose vtype is PostScript.

       The ToolTalk service may return one of the following errors in process-
       ing the Display request:

                The  file  that  was  alleged to contain the document does not

                The in-mode contents  argument  had  no  value  and  the  file
                attribute of the message was not set.

                The document is not a valid instance of the media type.

       See attributes(7) for descriptions of the following attributes:

       |Availability   | library/tooltalk |
       |Stability      | Committed        |
       ttmedia_ptype_declare(3), ttmedia_load(3); Intro, Deposit, Edit, Status

ToolTalk 1.3                     1 March 1996                       Display(4)