MultiCam Boards Documentation > MultiCam Documentation > MultiCam User Guide > MultiCam Basics > Signaling > Callback Signaling Information > Registration of Callback Function

Registration of Callback Function

A callback function should be registered to a channel or processor object before use. Only one callback function per object is supported.

Registering the callback function results into the creation in the application process of a separate thread dedicated to the callback function. This thread is maintained in a idle state until a signal occurs. There can be only one dedicated thread per channel or processor object.

A dedicated MultiCam function is provided for callback registration called McRegisterCallback. Here is the prototype.

MCSTATUS McRegisterCallback (
  MCHANDLE Instance,
  PMCCALLBACK CallBackFunction,
  PVOID Context
);

Item

Type

Description

McRegisterCallback

MCSTATUS

MultiCam API function.

Instance

MCHANDLE

Argument designating the channel or processor object to which the callback function is to be registered.

CallbackFunction

PMCCALLBACK

Argument pointing to the callback function defined by the user.If NULL, the callback function is removed from the specified object (un-registration).

Context

PVOID

Argument allowing for passing a user-defined value to the callback function.

Return Value

MCSTATUS

MC_OK or error code.