get_framegrabber_callbackT_get_framegrabber_callbackGetFramegrabberCallbackGetFramegrabberCallback (Operator)

Name

get_framegrabber_callbackT_get_framegrabber_callbackGetFramegrabberCallbackGetFramegrabberCallback — Query callback function of an image acquisition device.

Signature

get_framegrabber_callback( : : AcqHandle, CallbackType : CallbackFunction, UserContext)

Description

The operator get_framegrabber_callbackget_framegrabber_callbackGetFramegrabberCallbackGetFramegrabberCallbackGetFramegrabberCallback queries a callback function for the image acquisition device specified by AcqHandleAcqHandleAcqHandleAcqHandleacqHandle. If the callback function was registered via set_framegrabber_callbackset_framegrabber_callbackSetFramegrabberCallbackSetFramegrabberCallbackSetFramegrabberCallback before, CallbackFunctionCallbackFunctionCallbackFunctionCallbackFunctioncallbackFunction contains a pointer to it, otherwise NULL. Furthermore, UserContextUserContextUserContextUserContextuserContext contains a pointer to the user-specific context data that was set via set_framegrabber_callbackset_framegrabber_callbackSetFramegrabberCallbackSetFramegrabberCallbackSetFramegrabberCallback (or NULL).

With the parameter CallbackTypeCallbackTypeCallbackTypeCallbackTypecallbackType, you can select different callback types. Suggested values are:

'exception':: The image acquisition has raised an exception.
'exposure_end':: The exposure of the next image has been finished.
'exposure_start':: The exposure of the next image has been started.
'transfer_end':: A new image is ready to be fetched by grab_image_asyncgrab_image_asyncGrabImageAsyncGrabImageAsyncGrabImageAsync.

Depending on the functionality of the underlying API, additional values for CallbackTypeCallbackTypeCallbackTypeCallbackTypecallbackType are possible. All actually supported callback types of a specific image acquisition device can be queried by calling get_framegrabber_paramget_framegrabber_paramGetFramegrabberParamGetFramegrabberParamGetFramegrabberParam with the parameter 'available_callback_types'. For more details see the documentation of the specific image acquisition interface.

Attention

For a multithreaded application all image acquisition operators (as listed in open_framegrabberopen_framegrabberOpenFramegrabberOpenFramegrabberOpenFramegrabber) are an own group in which info_framegrabberinfo_framegrabberInfoFramegrabberInfoFramegrabberInfoFramegrabber, open_framegrabberopen_framegrabberOpenFramegrabberOpenFramegrabberOpenFramegrabber, close_framegrabberclose_framegrabberCloseFramegrabberCloseFramegrabberCloseFramegrabber and close_all_framegrabbersclose_all_framegrabbersCloseAllFramegrabbersCloseAllFramegrabbersCloseAllFramegrabbers are executed exclusively.

get_framegrabber_callbackget_framegrabber_callbackGetFramegrabberCallbackGetFramegrabberCallbackGetFramegrabberCallback runs in parallel with all non-exclusive operators inside and outside of this group.

Execution Information

Multithreading type: reentrant (runs in parallel with non-exclusive operators).
Multithreading scope: global (may be called from any thread).
Processed without parallelization.

Parameters

AcqHandleAcqHandleAcqHandleAcqHandleacqHandle (input_control) framegrabber → (handle)

Handle of the acquisition device to be used.

CallbackTypeCallbackTypeCallbackTypeCallbackTypecallbackType (input_control) string → (string)

Callback type.

Default value: 'transfer_end' "transfer_end" "transfer_end" "transfer_end" "transfer_end"

Suggested values: 'exception'"exception""exception""exception""exception", 'exposure_end'"exposure_end""exposure_end""exposure_end""exposure_end", 'exposure_start'"exposure_start""exposure_start""exposure_start""exposure_start", 'transfer_end'"transfer_end""transfer_end""transfer_end""transfer_end"

CallbackFunctionCallbackFunctionCallbackFunctionCallbackFunctioncallbackFunction (output_control) pointer → (integer)

Pointer to the callback function.

UserContextUserContextUserContextUserContextuserContext (output_control) pointer → (integer)

Pointer to user-specific context data.

Result

If the image acquisition device is open and the specified callback type is supported, the operator get_framegrabber_callbackget_framegrabber_callbackGetFramegrabberCallbackGetFramegrabberCallbackGetFramegrabberCallback returns the value 2 (H_MSG_TRUE). Otherwise an exception is raised.

Possible Predecessors

open_framegrabberopen_framegrabberOpenFramegrabberOpenFramegrabberOpenFramegrabber, set_framegrabber_callbackset_framegrabber_callbackSetFramegrabberCallbackSetFramegrabberCallbackSetFramegrabberCallback

Possible Successors

grab_imagegrab_imageGrabImageGrabImageGrabImage, grab_datagrab_dataGrabDataGrabDataGrabData, grab_image_startgrab_image_startGrabImageStartGrabImageStartGrabImageStart, grab_image_asyncgrab_image_asyncGrabImageAsyncGrabImageAsyncGrabImageAsync, grab_data_asyncgrab_data_asyncGrabDataAsyncGrabDataAsyncGrabDataAsync, set_framegrabber_paramset_framegrabber_paramSetFramegrabberParamSetFramegrabberParamSetFramegrabberParam, close_framegrabberclose_framegrabberCloseFramegrabberCloseFramegrabberCloseFramegrabber

Module

Foundation

Operators