Notes on Using This Function

  1. There is no way to require the user to use this function. It is not a required function so that the application can be tailored to run on any system.
  2. The buffer sizes returned represent the record sizes that are actually transmitted across the medium. For a DDM connection, the 8-byte header supplied in the Read and Write Structured Fields data buffer is stripped off and 1 byte containing the structured field AID value is prefixed. The application should compare the size of the actual data in the data buffer (which does not include the 8-byte header) with the buffer sizes returned by the Query Communications Buffer Size minus 1 byte. For destination/origin connections, the 8-byte header supplied in the Read and Write Structured Fields data buffer is stripped off and 9 bytes are then prefixed to the data. The application should compare the size of the actual data in the data buffer (which does not include the 8-byte header) with the buffer size returned by the Query Communications Buffer Size minus 9 bytes.
  3. The maximum buffer sizes returned represent the maximum number of bytes supported by the workstation hardware and by the emulator. The maximum buffer size can be used only if the host is also configured to accept at least these maximum sizes.
  4. The optimum buffer sizes returned represent the optimum number of bytes supported by the both the workstation hardware and the emulator. Some network configurations might set transmission limits smaller than these values. In these cases, the data transfer buffer size override value in the emulator configuration profile will be used for structured field support. The Query Communications Buffer Size will reflect any buffer size override values entered in the emulator configuration profile.
Parent topic: Query Communications Buffer Size (122)