4.2 Modifying, passing and returning strings
4.2.1 Use of Reference Arguments
4.2.2 Modifying a string in a C function
4.2.3 Passing a constant string
4.2.4 Returning a string via a buffer
4.2.5 Foreign string encodings
4.2.6 Foreign string line terminators
4.2.7 Mapping Nil to a Null Pointer
LispWorks Foreign Language Interface User Guide and Reference Manual - 13 Sep 2005