NAME
    InstallClipRegion -- Install clip region in layer

SYNOPSIS
    oldclipregion = InstallClipRegion( l,  region )
    d0                                 a0  a1

    struct Region *InstallClipRegion( struct Layer *, struct Region *);

FUNCTION
    Installs a transparent Clip region in the layer. All
    subsequent graphics calls will be clipped to this region.
    You MUST remember to call InstallClipRegion(l,NULL) before
    calling DeleteLayer(l) or the Intuition function CloseWindow()
    if you have installed a non-NULL ClipRegion in l.

INPUTS
    l - pointer to a layer
    region - pointer to a region

RESULTS
    oldclipregion - The pointer to the previous ClipRegion that
        was installed. Returns NULL if no previous ClipRegion installed.

        Note: If the system runs out of memory while computing the
            resulting ClipRects the LAYERS_CLIPRECTS_LOST bit will
            be set in l->Flags.

BUGS
    If the system runs out of memory during normal layer operations,
    the ClipRect list may get swept away and not restored.
    As soon as there is enough memory and the layer library
    gets called again the ClipRect list will be rebuilt.

SEE ALSO
    BeginUpdate EndUpdate,
    graphics/layers.h, graphics/clip.h, graphics/regions.h