LoadedJavaObjects[] returns a list of the Java objects that have been sent to Mathematica (and not yet released with ReleaseJavaObject).

UseFrontEnd[expr] evaluates expr in an environment where the kernel can make use of the services of the notebook front end.

$FrontEndInitializationFunction is a function that you can assign to execute when the front end link is first established by ConnectToFrontEnd[].

MLINK getMathLink (WolframLibraryData libData) gets a MathLink connection to use for evaluations in Mathematica.

int MTensor_clone (MTensor f, MTensor *t) is a library callback function that puts a clone of f into *t.

mcomplex*MTensor_getComplexData (MTensor t) gets an array of the data elements of an MTensor of complex type.

mint*MTensor_getIntegerData (MTensor t) gets an array of the data elements of an MTensor of integer type.

double*MTensor_getRealData (MTensor t) gets an array of the data elements of an MTensor of real type.

int MTensor_new (mint type, mint rank, mint const*dims, MTensor*pres) is a library callback function that creates a new MTensor.

CallingConvention is an option to DefineDLLFunction that specifies what calling convention the DLL function uses.