Path: utzoo!attcan!uunet!lll-winken!ncis.llnl.gov!helios.ee.lbl.gov!pasteur!ucbvax!gergle.UUCP!greg
From: greg@gergle.UUCP
Newsgroups: comp.windows.news
Subject: Re:  testing cps message queue
Message-ID: <8901220300.AA19541@frame.com>
Date: 23 Jan 89 20:02:59 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 44


>I have C plus CPS code that would really benefit from knowing when there is
>no input waiting  on PostScriptInput (ie. all the current cps commands from
>the NeWS server have been handled).  One application involves holding a
>repaint request until all other current requests (user input) have been
>handled.
>Could someone please tell me how to do this?  I am using a sun4-110 with
>OS4.01?

Here is a code frag which works for me. I have never tried running under
OS4.0. Please let me know if it works. block would be false in your case.
EVENTL is the minimum event length you expect to read.

	-greg.



	if(block) 
                avail = EVENTL;
        else {
                avail = psio_availinputbytes(PostScriptInput);
                if(avail < EVENTL) 
			{
                         ioctl(psio_fileno(PostScriptInput),FIONREAD,&bytes);
                         avail += bytes;
                        }
                }

        while(avail >= EVENTL) {
                if(psio_error(PostScriptInput)) {
                        fprintf(stderr,"PostScriptInput error\n"); 
                        exit(1);
                        }


                c = psio_getc(PostScriptInput);

	/* handling of input, CPS typed reads */
	/* handling of input, CPS typed reads */
	/* handling of input, CPS typed reads */
	/* handling of input, CPS typed reads */

                avail = psio_availinputbytes(PostScriptInput);
                }