Method for calling a function in a function-oriented programming language, such as C, from an object-oriented programming language, such as JAVA, where recursive calling of a serialization method (toX) stores the contents of the fields used in the structure in a data string in a linearized order corresponding to a format string, the linearized order having type indicators, and this data string is converted into a memory map of the structure by a packing function, and the function in the function-oriented programming language is called using the memory map as a parameter.