vlgetnextvalid(3dm)

NAME
     vlGetNextValid, vlGetLatestValid, vlGetActiveRegion, vlGetNextFree,
     vlGetDMediaInfo, vlGetImageInfo, vlPutValid, vlPutFree - VL buffer
     management routines

SYNOPSIS
     #include <dmedia/vl.h>

     void *vlGetActiveRegion(VLServer vlServer, VLBuffer buffer, VLInfoPtr info);
     DMediaInfo *vlGetDMediaInfo(VLServer vlServer, VLBuffer buffer,
                         VLInfoPtr info);
     DMImageInfo *vlGetImageInfo(VLServer vlServer, VLBuffer buffer,
                         VLInfoPtr info);

     VLInfoPtr vlGetLatestValid(VLServer vlServer, VLBuffer buffer);
     VLInfoPtr vlGetNextFree(VLServer vlServer, VLBuffer buffer, int size);
     VLInfoPtr vlGetNextValid(VLServer vlServer, VLBuffer buffer);

     int vlPutFree(VLServer vlServer, VLBuffer buffer);
     int vlPutValid(VLServer vlServer, VLBuffer buffer);

DESCRIPTION
     vlGetActiveRegion returns a pointer to the video frame data.  The region
     is determined by the settings of the VL_OFFSET controls.  The default is
     the region of valid video data.

     vlGetDMediaInfo returns a pointer to a DMediaInfo struct containing
     general information.

     vlGetImageInfo returns a pointer to a DMImageInfo struct containing image
     specific info.

     vlGetLatestValid returns the info struct of the most recently received
     frame.

     vlGetNextFree returns the info struct of the next free buffer.

     vlGetNextValid returns the info struct of the next available frame.

     vlPutFree frees any frames that were acquired via vlGetLatestValid or
     vlGetNextValid.

     vlPutValid marks a buffer as ready to be sent.

RETURN VALUE
     Upon successful completion, vlGetLatestValid, vlGetNextFree,
     vlGetNextValid return valid pointers, otherwise a value of NULL is
     returned. If a value returned is NULL, the buffer should be checked with
     vlBufferDone(3dm) to see if more data can be written to the buffer. It is
     possible to get a NULL return value without a failure, if there is no
     buffer available. In this case vlGetErrno will not return a useful error.
     Upon successful completion vlGetActiveRegion, vlGetDMediaInfo,
     vlGetImageInfo return valid pointers, otherwise they return NULL.

     vlPutFree and vlPutValid return VLSuccess on successful completion,
     otherwise a value of -1 is returned. In all failure cases, vlErrno is set
     to indicate the error.

SEE ALSO
     vlCreateBuffer(3dm), vlRegisterBuffer(3dm)