gpib_spreq(3)                       CLIX                       gpib_spreq(3)



  NAME

    gpib_spreq - Conducts a serial poll of a GPIB device

  LIBRARY

    Intergraph Device Library (libix.a)

  SYNOPSIS

    #include <sys/xio/xerr.h>

    int gpib_spreq(
      int channel ,
      char *tdev ,
      int timeout ,
      char *poll );

  DESCRIPTION

    The gpib_spreq() function conducts a serial poll of a specific device on
    the General Purpose Interface Bus (GPIB) channel.  The tdev parameter
    points to the primary address of the device to be serially polled.

    Upon completion, the status location pointed to by poll contains the
    serial poll response.  If an error occurs during the request, the serial
    poll response is not valid.

    Abort timeouts are enabled by setting timeout to the number of / second
    intervals the driver waits for the serial poll response.  A value of
    indicates a timeout is not desired.

    To initiate the serial poll request, the system controller is put in an
    active state, and the following GPIB messages are sent on the GPIB
    channel:

    UNL   Unlisten

    UNT   Untalk

    SPE   Serial Poll Enable

    TAG   Talk Address Group

    Following this message sequence, the controller enters a standby state and
    reads the serial poll response from the GPIB device.  The controller is
    put in an active state, and the following GPIB messages are transmitted to
    ensure the device does not corrupt serial polls of other GPIB devices:

    SPD   Serial Poll Disable




  2/94 - Intergraph Corporation                                              1

  gpib_spreq(3)                       CLIX                       gpib_spreq(3)



    UNT   Untalk

  RETURN VALUES

    Upon successful completion, a value of  is returned.  Otherwise, one of
    the following failure codes is returned.

  ERRORS

    The gpib_spreq() function will fail if one of the following is true:

    [XIO_FAILURE]
           The system does not contain the driver needed to support this
           request.

    [GPIB_OUT_OF_RANGE]
           The specified channel is beyond the maximum allowed.

    [GPIB_NOT_OPEN]
           The specified channel is not open.

    [GPIB_NOT_OWNER]
           Channel is currently open by another process.

    [GPIB_DEVICE_INVALID]
           The specified primary address was incorrect.

    [GPIB_TIMEOUT]
           The current request aborted before the system controller received
           the GPIB serial poll response from the device.

    [GPIB_HARDWARE_CHECK]
           A hardware error occurred during the serial poll request.  For
           example, the specified primary address may not correspond to any of
           the GPIB devices on channel.

    [BAD_DATA_BUFFER_ADDRESS]
           Tdev or poll points to an invalid memory address.

  RELATED INFORMATION

    Functions:  gpib_open(3), gpib_service(3), gpib_ppreq(3)

    Files:  xgpib(7)










  2                                              Intergraph Corporation - 2/94