void GLAPIENTRY glGetHistogramParameterfv( GLenum target,
                                                  GLenum pnam )
       void GLAPIENTRY glGetHistogramParameteriv( GLenum target,
                                                  GLenum pnam )

PARAMETERS
       target  Must be one of GL_HISTOGRAM or GL_PROXY_HISTOGRAM.

       pnam    The name of the parameter to  be  retrieved.   Must  be  one  of
               GL_HISTOGRAM_WIDTH,  GL_HISTOGRAM_FORMAT, GL_HISTOGRAM_RED_SIZE,
               GL_HISTOGRAM_GREEN_SIZE,                 GL_HISTOGRAM_BLUE_SIZE,
               GL_HISTOGRAM_ALPHA_SIZE,     GL_HISTOGRAM_LUMINANCE_SIZE,     or
               GL_HISTOGRAM_SINK.

       _param3 Pointer to storage for the returned values.

DESCRIPTION
       glGetHistogramParameter is used to query parameter values for  the  cur‐
       rent  histogram  or for a proxy.  The histogram state information may be
       queried by calling glGetHistogramParameter with a target of GL_HISTOGRAM
       (to   obtain   information   for   the   current   histogram  table)  or
       GL_PROXY_HISTOGRAM (to obtain information from the most recent proxy re‐
       quest) and one of the following values for the pnam argument:

           ────────────────────────────────────────────────────────────────
           Parameter                 Description
           ────────────────────────────────────────────────────────────────
           GL_HISTOGRAM_WIDTH        Histogram table width
           GL_HISTOGRAM_FORMAT       Internal format
           GL_HISTOGRAM_RED_SIZE     Red component counter size, in bits
           GL_HISTOGRAM_GREEN_SIZE   Green component counter size, in bits

       ────────────────────────────────────────────────────────────────────────
       Parameter                     Description
       ────────────────────────────────────────────────────────────────────────
       GL_HISTOGRAM_BLUE_SIZE        Blue component counter size, in bits
       GL_HISTOGRAM_ALPHA_SIZE       Alpha component counter size, in bits
       GL_HISTOGRAM_LUMINANCE_SIZE   Luminance component counter size, in bits
       GL_HISTOGRAM_SINK             Value of the sink parameter
       ────────────────────────────────────────────────────────────────────────

NOTES
       glGetHistogramParameter  is  present  only if GL_ARB_imaging is returned
       when glGetString is called with an argument of GL_EXTENSIONS.

ERRORS
       GL_INVALID_ENUM is generated if target is not one of the allowable  val‐
       ues.

       GL_INVALID_ENUM is generated if pnam is not one of the allowable values.

       GL_INVALID_OPERATION is generated if glGetHistogramParameter is executed