-unsigned int hash_bytes (const void *, size_t, unsigned int basis);
-unsigned int hash_string (const char *, unsigned int basis);
-unsigned int hash_int (int, unsigned int basis);
-unsigned int hash_double (double, unsigned int basis);
-unsigned int hash_pointer (const void *, unsigned int basis);
+unsigned int hash_bytes (const void *, size_t, unsigned int basis) WARN_UNUSED_RESULT;
+unsigned int hash_string (const char *, unsigned int basis) WARN_UNUSED_RESULT;
+unsigned int hash_int (int, unsigned int basis) WARN_UNUSED_RESULT;
+unsigned int hash_double (double, unsigned int basis) WARN_UNUSED_RESULT;
+unsigned int hash_pointer (const void *, unsigned int basis) WARN_UNUSED_RESULT;