CTM_$RELEASE_PV CTM Calls CTM_$RELEASE_PV
NAME
ctm_$release_pv - decrements pixel value use counts.
FORMAT
ctm_$release_pv (count, option, plane, pixel_values, status)
DESCRIPTION
The ctm_$release_pv decrements use counts for pixel values allocated to
the calling process. A process should call ctm_$release_pv to free up
pixel values it no longer needs so the CTM can allocate them to other
processes. Any unreleased pixel values allocated to a process will have
their use counts decremented by the CTM when that process terminates.
Input Parameters
count
Specifies the number of pixel values (or pixel value pairs) to be
released. This is a 2-byte integer.
option
Together with plane, this defines how ctm_$release_pv will interpret
pixel_values. This parameter is in ctm_$alloc_options_t format,
which is a 2-byte integer. Although this argument is a small set
type, the CTM currently accepts only one option at a time, so choose
only one from the following:
ctm_$contiguous
Decrement the use count for count contiguous pixel values, start-
ing from the first pixel value passed in pixel_value. When
specifying ctm_$contiguous, pass only the lowest pixel value
whose use count is to be decremented in the pixel_values argu-
ment.
ctm_$zero_only
Decrement the use counts for the count pixel values supplied in
pixel_values. The plane value is redundant.
ctm_$one_only
Decrement the use counts for the count pixel values supplied in
pixel_values. The plane value is redundant.
ctm_$both
Decrement the use counts for count pairs of pixel values, where
the members of each pair differ only in the plane bit. When
specifying ctm_$both, pass only the lowest pixel value of each
pair of pixel values to be decremented in the pixel_values argu-
ment.
plane
Specifies a bit plane used together with option to define the pixel
values supplied in pixel_values. This parameter is a 2-byte
integer. plane specifies a pixel value bit position or a plane in
the display bitmap. Unless option is ctm_$both, the value of plane
is ignored by ctm_$release_pv.
pixel_values
An array of pixel values whose use counts are to be decremented by
ctm_$release_pv, in ctm_$pixel_value_vector_t format. This parame-
ter is an array of 4-byte integers. If option is ctm_$continuous,
then pass only one pixel value in pixel_values. Otherwise,
pixel_values should contain count pixel values.
Output Parameters
status
The completion status, in status_t format.
NOTES
The ctm_$release_pv routine will fail when passed a pixel value with a
use count of 0, and it will return with ctm_$not_allocated in status when
passed a pixel value whose use count hasn't been incremented by the cal-
ling process at or above the current program level.