close_framegrabber — Close specified image acquisition device.
close_framegrabber( : : AcqHandle : )
The operator close_framegrabber closes the image acquisition device specified by AcqHandle. In particular, allocated memory for data buffers is released and the image acquisition device is made available for other processes.
Basically an image acquisition handle AcqHandle cannot be used in multiple threads. However, possible exceptions are described in the specific reference documentation of the respective image acquisition interface. Different image acquisition handles can be used safely with different threads for each handle.
For a multithreaded application all image acquisition operators (as listed in open_framegrabber) are an own group in which info_framegrabber, open_framegrabber, close_framegrabber and close_all_framegrabbers are executed exclusively.
Thus, info_framegrabber, open_framegrabber, close_framegrabber and close_all_framegrabbers block the concurrent execution of all other operators within this group, but run in parallel with all non-exclusive operators outside of this group.
Handle of the image acquisition device to be closed.
If the specified image acquisition device could be closed, close_framegrabber returns the value 2 (H_MSG_TRUE). Otherwise an exception is raised.