This paper attempts to evaluate Larch/C++, a formal specification language, as a means of more unambiguously documenting the interface specifications of C++ class libraries. In particular, the Microsoft Foundation Class Library is examined to demonstrate some of the advantages and disadvantages of using Larch/C++. Several different examples are presented with analysis. The reader is assumed to have some familiarity with C++ and the idea of formal specification, but need not know the Larch approach to formal specification.