MultiCam Boards Documentation > MultiCam Documentation > MultiCam User Guide > MultiCam Basics > Signaling > Common Signaling Information > Signal Information Structure

Signal Information Structure

A dedicated C structure of the type MCSIGNALINFO is specified to provide information on a specific MultiCam signal issued by a specific channel object.

The signal information type is declared in the MultiCam system MultiCam.h header file.

There are three usages:

The user-written code implementing a callback function is informed on the signal that caused the callback with an argument of the signal information type.

The waiting function returns the information of the thread releasing signal with an argument of the signal information type.

This signal information structure can be retrieved with the MultiCam function McGetSignalInfo, which specifies a target channel or processor. In that case, the structure holds the information associated to the last signal issued by the target object.

Here is the signal information structure definition:

typedef struct {
  PVOID Context,
  MCHANDLE Instance,
  MCSIGNAL Signal,
  UINT32 SignalInfo,
  UINT32 Reserved,
} MCSIGNALINFO, *PMCSIGNALINFO;


Structure member

Usage with callback

Usage with waiting function

Usage with retrieving function

Context

Argument passed "as-is" from the registration of the callback function.

Not applicable.

Not applicable.

Instance

Handle designating the object owning the signal that issued the callback.

Handle designating the object owning the signal that released the waiting thread.

Handle designating the object targeted by the retrieving function.

Signal

Identifier value of the signal that issued the callback.

Identifier value of the signal that released the waiting thread.

Identifier value of the last signal issued by the target object.

SignalInfo

Information specific to the signal that issued the callback.

Information specific to the signal that released the waiting thread

Information specific to the last signal issued by the target object.