VLCREATEBUFFER(3dm)VLCREATEBUFFER(3dm)NAME
vlCreateBuffer, vlDestroyBuffer - IRIS VL buffer create and destroy
routines
SYNOPSIS
#include <dmedia/vl.h>
VLBuffer vlCreateBuffer(VLServer svr, VLPath path, VLNode node, int nframes);
int vlDestroyBuffer(VLServer svr, VLBuffer buffer);
DESCRIPTION
vlCreateBuffer creates and returns a handle to a buffer which can then be
registered with a path and used to send or receive video data.
A VLBuffer consists of a list of frame-sized regions of memory each with
an associated header block. Buffers are needed for transferring data to
or from memory nodes. To receive a frame, the reader calls one of
vlGetNextValid or vlGetLatestValid , and to free that frame calls
vlPutFree. To send a frame, the writer calls vlGetNextFree, copies the
data to be sent into the acquired buffer, and then vlPutValid to send
that frame.
Various controls affect buffer size. Setting controls which affect frame
size should be done prior to calling vlCreateBuffer. These controls
include VL_CAP_TYPE, VL_PACKING, VL_SIZE, VL_ZOOM, VL_OFFSET and
VL_TIMING.
vlDestroyBuffer destroys a buffer and frees any associated resources.
DIAGNOSTICS
vlCreateBuffer returns a buffer handle upon successful completion.
Otherwise, NULL is returned and vlErrno is set to indicate the error.
vlDestroyBuffer returns 0 if the server handle is valid, otherwise it
returns -1 and sets vlErrno to VLBadServer.
SEE ALSOvlCreatePath(3dm), vlBeginTransfer(3dm), vlRegisterBuffer(3dm),
vlGetNextValid(3dm), vlSetControl(3dm)
Page 1
