Technical Reference:SignalSharingClient Library

The SignalSharingClient library provides a SignalSharing client, wrapped into a C interface. It may be used to tap into signal and state data at any point of processing from external applications. The SignalSharingClient library can be used from any programming language that allows using a shared library (DLL). Although the SignalSharingClient library is written in C++, its DLL interface is plain C, and can be used with compiled languages such as C, C++, C#, Pascal, but also with interpreted languages that can call functions in a DLL, such as Python, Matlab, VisualBasic, etc. Interfacing with Java requires a JNI (Java Native Interface) wrapper, which is currently not provided by BCI2000.

Functions provided by the Library

SSC_RESULT SSC_CreateConnector(const char* listeningAddress, SSC_HANDLE*)

Create a connector object, and obtain a handle to it. A connector object is necessary to handle a connection to BCI2000, and is specified as the first argument of the remaining SignalSharingClient library functions. The listening address is in the format <IP>:<port> with <IP> being a name or numeric address.

SSC_RESULT SSC_DeleteConnector(SSC_HANDLE)

Delete a connector object. Must be called when connector object is no longer used.

SSC_RESULT SSC_RegisterSignalCallback(SSC_HANDLE, SSC_CALLBACK, void* refdata)

Register a callback to be called whenever new signal data is available. For each connector object, it is only possible to register one signal callback at a time. To unregister a signal callback, call SSC_RegisterSignalCallback() with a nullptr argument. Use the <refdata> argument to specify auxiliary data which will be provided to the callback function when it is called.

SSC_RESULT SSC_RegisterStatesCallback(SSC_HANDLE, SSC_CALLBACK, void* refdata)

Register a callback to be called whenever new state data is available. For each connector object, it is only possible to register one states callback at a time. To unregister a signal callback, call SSC_RegisterStatesCallback() with a nullptr argument. Use the <refdata> argument to specify auxiliary data which will be provided to the callback function when it is called.

SSC_RESULT SSC_RegisterParametersCallback(SSC_HANDLE, SSC_CALLBACK, void* refdata)

Register a callback to be called whenever new parameter data is available. For each connector object, it is only possible to register one parameters callback at a time. To unregister a signal callback, call SSC_RegisterParametersCallback() with a nullptr argument. Use the <refdata> argument to specify auxiliary data which will be provided to the callback function when it is called.

SSC_RESULT SSC_LockSignal(SSC_HANDLE, const double** pSignal, int* channels, int* samples, const char* const** channelNames)

Lock signal data and obtain signal information. Typically, this function will be called from a signal callback. Locking blocks the arrival of new signal data, so call SCC_ReleaseSignal() as soon as possible. All pointer arguments are optional, may be nullptr.

SSC_RESULT SSC_ReleaseSignal(SSC_HANDLE)

Releases a locked signal. Call this function as soon as you are done with forwarding or processing signal data.

SSC_RESULT SSC_LockStates(SSC_HANDLE, const double**, int* count, int* samples, const char* const** pStateNames)

Lock state data and obtain state information. Typically, this function will be called from a state callback. Locking blocks the arrival of new state data, so call SCC_ReleaseStates) as soon as possible. All pointer arguments are optional, may be nullptr.

SSC_RESULT SSC_ReleaseStates(SSC_HANDLE)

Releases locked state information. Call this function as soon as you are done with forwarding or processing state data.

SSC_RESULT SSC_LockParameters(SSC_HANDLE, const char* const** parameterLines, int* count)

Lock parameter data and obtain parameter information. Typically, this function will be called from a parameter callback. Locking blocks the arrival of new parameter data, so call SCC_ReleaseParameters) as soon as possible. All pointer arguments are optional, may be nullptr.

SSC_RESULT SSC_ReleaseParameters(SSC_HANDLE)

Releases locked parameter information. Call this function as soon as you are done with forwarding or processing parameter data.

SSC_RESULT SSC_GetSignalDimensions(SSC_HANDLE, int* channels, int* samples)

Obtain signal dimensions for use with SSC_PushSignal().

SSC_RESULT SSC_PushSignal(SSC_HANDLE, const double* pSignal)

Push signal data. The pSignal pointer must point to a valid memory area that is at least as large as determined by a previous call to SSC_GetSignalDimensions. Pushing signal data will have no effect unless SSC_Commit() is called.

SSC_RESULT SSC_PushState(SSC_HANDLE, const char* name, unsigned int value)

Push a state value. Pushing a state value will have no effect unless SSC_Commit() is called.

SSC_RESULT SSC_Commit(SSC_HANDLE)

Commit pushed signal and state data to BCI2000. Any previously pushed signal or state data will be transmitted to BCI2000 when this function is called.

See also

Technical Reference:BCI2000Remote Library, Programming Reference:BCI2000Remote Class, Contributions:BCI2000Command, Contributions:BCI2000PresentationLink, Contributions:Applications