A handle to a Screen buffer
#include <screen/screen.h>
typedef struct _screen_buffer* screen_buffer_t;
A buffer is an area of memory that stores pixel data. Although a buffer can be created in the scope of a context, it can't be used by Screen unless it's attached to a window, stream, or pixmap. Multiple buffers can be associated with a window or stream, but only one buffer can be associated with a pixmap.
For more information, see the Resource Sharing chapter of the Screen Developer's Guide or the Buffers section of the library reference.