Bernd Jendrissek writes: No. You built the structure, you clean it up. Yes. No. ldap_mods_free() is just a helper function you could use if you did build the structure with malloc and strdup. Or better yet, with ber_memalloc and ber_strdup. (These are wrappers needed on Windows or something because IIRC memory must be freed by the same DLL which allocated it.) This is just a case of "const poisoning" - once you slap a "const" at a declaration, it can easily spread out, demanding "const"s elsewhere too. C started out without "const", even on string literals (which may not be modified). C libraries and programs do tend to grow more consts over the year, but C++ has gone much farther. For one thing, because it has features like const_cast<> and mutable which make unwanted consts less painful. When defining a library data structure, one has to decide on things like what to constify. The API has no reason to assume that the data is intended to be const - in fact, ldap_mods_free() would look strange if it was. Stranger than in C++, anyway. -- Regards, Hallvard