#include <nng/nng.h>
const char * nng_strerror(int err);

The returned error message is provided in US English, but in the
future locale-specific strings may be presented instead.

The specific strings associated with specific error messages are
subject to change. Therefore applications must not depend on the message, but may use them verbatim when supplying information to end-users, such as in diagnostic messages or log entries.