vlgetcontrolinfo(3dm)

NAME
     vlGetControlInfo, vlFreeControlInfo - get and free information about VL
     controls

SYNOPSIS
     #include <dmedia/vl.h>

     VLControlInfo *vlGetControlInfo(VLServer svr, VLPath path,
          VLNode node, VLControlType type);

     int vlFreeControlInfo(VLServer svr, VLControlInfo *info);

PARAMETERS
     svr      Specifies the video server handle.

     path     Specifies the path of interest.

     node     Specifies the source or drain of interest.  May be VL_ANY if
              either a source or drain control is acceptable, or if the
              control is not associated with either a source or drain.

     type     Specifies the control type of interest.

     info     Specifies a pointer to a VLControlInfo structure which was
              previously allocated by vlGetControlInfo.

DESCRIPTION
     The vlGetControlInfo function is used to find information about valid
     settings for a VL control. It uses the path, node, and type parameters to
     locate a VL control, and returns a VLControlInfo structure which
     describes the desired control.

     The returned VLControlInfo structure will describe the control in one of
     two ways.  It will specify either the range (or ranges) of values
     supported by the control, or it will specify the set of discrete values
     supported by the control.  If the VL control is described by a range of
     values, then the VLControlInfo structure will indicate a value range with
     a pointer to an array of VLFractionRange structures.  If the VL control
     is described by a set of discrete values, then the VLControlInfo
     structure will indicate the legal set of values with a pointer to an
     array of VLControlItem structures.  Only one of these two arrays will
     exist in the VLControlInfo structure.

     For example, a control for VL_SIZE has a value of type VL_CT_XY, which
     represents the legal range of (X, Y) coordinates for this control, and
     may be described by a two entry array of type VLFractionRange with one
     entry for the X coordinate, and one for the Y coordinate.  A control for
     VL_FORMAT has a value of type VL_CT_INT, which represents the set of
     legal video formats for this control, and may be described by an array of
     type VLControlItem with one entry for each possible value which the
     control may take.
     The vlFreeControlInfo function should be used to deallocate the
     VLControlInfo data which has been allocated by a call to
     vlGetControlInfo.

RETURN VALUE
     If successful, vlGetControlInfo returns a pointer to a VLControlInfo
     structure which describes the specified control, otherwise it returns
     NULL.

     If successful, vlFreeControlInfo returns VLSuccess, otherwise it returns
     a VL error code.

SEE ALSO
     vlGetControl(3dm), vlSetControl(3dm)