A method and apparatus for storing a function specification file is described. In an exemplary method, the function specification field is capable for providing other software to facilitate execution of an application in a second operating system with the presence of a first operating system and the application is compiled for the first operating system. In another exemplary method, a preprocessor receives the function specification file comprising function definition data for a library function. The preprocessor processes the function definition data to generate header information and function code for the function. In another exemplary method, the preprocessor generates an automatic logging framework for the interposing library based on the function definition data. Further, a function in an interposing library logs calls to a corresponding library function.