fg_alloc(3)                         CLIX                         fg_alloc(3)



  NAME

    fg_alloc - Allocates a frame grabber

  LIBRARY

    Intergraph Device Library (libix.a)

  SYNOPSIS

    #include <sys/xio/xerr.h>

    #include <sys/xio/xfg.h>

    int fg_alloc(
      int fgno ,
      struct fg_info *info ,
      int excl );

  PARAMETERS

    fgno   The location of the frame grabber on the Shared Resource (SR) Bus.

    info   A pointer to an fg_info structure

    excl   Exclusive access flag

  DESCRIPTION

    The fg_alloc() function allocates a frame grabber for an application to
    use.  If excl is nonzero, the calling process has exclusive access to the
    frame grabber until it deallocates the frame grabber or the process exits.
    If excl is 0, another process may allocate the same frame grabber.

    The fgno parameter specifies the location of the frame grabber on the
    Shared Resource (SR) Bus.  The frame grabber in the lowest SR Bus slot
    will be addressed by 0.  This number is used with all subsequent calls.

    The info parameter points to an fg_info structure as defined in the header
    file <sys/xio/xfg.h>:

    struct fg_info {
         int  i_slot;      /* frame grabber hardware slot number */
         long *i_fb0_addr; /* frame buffer 0 address */
         long *i_fb1_addr; /* frame buffer 1 address */
    }

    The info structure will be filled in upon return by fg_alloc().  The
    i_fb0_addr and i_fb1_addr members point to the virtual addresses of frame
    buffers 0 and 1 (respectively) of the frame grabber.  Each buffer consists
    of 256K longwords organized as an array of 512 x 512, 32-bit pixels.  The



  2/94 - Intergraph Corporation                                              1

  fg_alloc(3)                         CLIX                         fg_alloc(3)



    format for each 32-bit pixel is as follows:

    Byte   Description

    0      red color component

    1      green color component

    2      blue color component

    3      not used

  CAUTIONS

    Cooperation among processes must occur when sharing a frame grabber.

  RETURN VALUES

    Upon successful completion, a value of 0 is returned.  Otherwise, one of
    the failureollowing codes is returned.

  ERRORS

    The fg_alloc() function will fail if one of the following are true:

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

    [FG_NOT_PRESENT]
           A frame grabber is not available for allocation.

    [BAD_DATA_BUFFER_ADDRESS]
           The info or fgno parameter points to a nonwritable memory address.

    [FG_BUSY]
           Another user allocated the frame grabber for exclusive use.  Or,
           this call requested exclusive use and another process allocated the
           frame grabber for nonexclusive use.

    [FG_RESOURCE_ERROR]
           Not enough virtual memory is available to map the frame buffer into
           the user's memory space.

  RELATED INFORMATION

    Functions:  fg_dealloc(3)







  2                                              Intergraph Corporation - 2/94