VLBUFFERRESET(3dm)VLBUFFERRESET(3dm)NAME
vlBufferReset, vlBufferDone, vlBufferGetFd, vlBufferAdvise, vlNodeGetFd,
vlDMBufferResetNode - VL buffer state management routines
SYNOPSIS
#include <dmedia/vl.h>
int vlBufferReset(VLServer svr, VLBuffer buffer);
int vlBufferDone(VLBuffer buffer);
int vlBufferGetFd(VLBuffer buffer);
int vlBufferAdvise(VLBuffer buffer, int advice);
int vlNodeGetFd(VLServer vlServer, VLPath path, VLNode node);
int vlDMBufferResetNode(VLServer vlServer, VLPath path, VLNode node);
PARAMETERS
svr Specifies the server handle.
path Specifies the path handle.
node Specifies the node handle.
buffer Specifies the buffer handle.
advice Specifies the advice for the buffer.
DESCRIPTION
vlBufferReset will reset the buffer so that the done flag is not set, and
the buffer can have data written into it again.
vlBufferDone returns the value of the buffer done flag. If this flag is
positive, the buffer cannot have any valid data written into it. In this
case vlGetNextFree(3dm) will always fail.
vlBufferGetFd returns a file descriptor that can be used with select(2)
to determine if there are frames available to be read (the file
descriptor is readable) or written (the file descriptor is writable).
This file descriptor will be invalid when the buffer is destroyed with
vlDestroyBuffer.
vlNodeGetFd returns a file descriptor that can be used with select(2) to
determine if there is video data available to be read.
vlDMBufferResetNode can be called after vlEndTransfer to clear the
specified memory node of any outstanding DMBuffers sent to the specified
node.
Both vlNodeGetFd and vlDMBufferResetNode can only be used after a
DMbufferPool has been registered to a path and node using
vlDMPoolRegister(3dm). Video data must be read using
vlDMBufferGetValid(3dm).
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VLBUFFERRESET(3dm)VLBUFFERRESET(3dm)
vlBufferAdvise tells the library information about how the buffer will be
used. VL_BUFFER_ADVISE_NOACCESS VL_BUFFER_ADVISE_ACCESS
RETURN VALUE
Upon successful completion, vlBufferReset will return VLSuccess,
otherwise -1 is returned. vlBufferDone will return >= 0 value on
success, and -1 otherwise. vlBufferGetFd will return >= 0 value on
success, and -1 otherwise.
CAVEATS
vlNodeGetFd and vlDMBufferResetNode return -1 with vlErrno set to
VLAPIConflict on the O2 platform. See vlintro(3dm) for a complete
listing of compatible and incompatible routines.
SEE ALSOvlCreateBuffer(3dm), vlGetNextFree(3dm), vlDMPoolRegister(3dm),
vlDMBufferGetValid(3dm), vlintro(3dm)
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