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  1. From: zodiac@darkness.gun.de (Ralph Seichter)
  2. Subject: Async I/O problem, can you help?
  3. Date: Mon, 1 Apr 96 20:16:00 CET
  4. Message-ID: <zpaf43aCY70MZ1@da23.darkness.gun.de>
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  9. Newsgroups: comp.sys.amiga.programmer
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  11.  
  12. I have written a small program to experiment with async I/O operations,
  13. which first opens the serial device (or the "duart.device" in my case),
  14. then spawns a child process to handle the device input, and finally sends
  15. a string to my modem so I get data transmitted back.
  16.  
  17. The problem I experience is that the following statements don't do what
  18. should (see "device.c/handleDeviceInput"):
  19.  
  20.    while (!(signals & SIGBREAKF_CTRL_C))
  21.    {
  22.        if (!sdi.pending)
  23.            startRead(&serInput, 1);
  24.  
  25.        Printf("Waiting for signals\n");
  26.        signals = Wait(sdi.sigRead | SIGBREAKF_CTRL_C);
  27.  
  28.        if (signals & sdi.sigRead)
  29.        {
  30.            Printf("Got device signal\n");
  31.            if (CheckIO((struct IORequest *)sdi.ior))
  32.            {
  33.                sdi.pending = FALSE;
  34.                Printf("Device input '%lc'\n", serInput);
  35.            }
  36.        }
  37.    }
  38.    stopRead();
  39.  
  40. SendIO() sends a read request, then I wait for Ctrl-C and the message
  41. port's signal bit. But the latter never arrives! If I use 'Scout' to send
  42. the proper signal manually, CheckIO() finds the read request complete and
  43. the correct byte is printed. The very same code segment works just fine if
  44. I don't spawn it as a child process.
  45.  
  46. I include the sources so you can see what 'sdi' etc. is all about. Thanks
  47. for every hint.
  48.  
  49.     -Ralph
  50.  
  51.  
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  119. ``
  120. end
  121. size 2933
  122.