krb5_is_thread_safe man page
krb5_is_thread_safe — is the Kerberos library compiled with multithread support
Kerberos 5 Library (libkrb5, -lkrb5)
TRUE if the library was compiled with with multithread support. If the library isn't compiled, the consumer have to use a global lock to make sure Kerboros functions are not called at the same time by different threads.