diff --git a/scripts/data_files/error.fmt b/scripts/data_files/error.fmt
index 7fed598..3be94bd 100644
--- a/scripts/data_files/error.fmt
+++ b/scripts/data_files/error.fmt
@@ -82,8 +82,6 @@
     return( NULL );
 }
 
-void (*mbedtls_test_hook_error_add)( int, int, const char *, int );
-
 void mbedtls_strerror( int ret, char *buf, size_t buflen )
 {
     size_t len;
@@ -164,4 +162,8 @@
 
 #endif /* MBEDTLS_ERROR_C */
 
+#if defined(MBEDTLS_TEST_HOOKS)
+void (*mbedtls_test_hook_error_add)( int, int, const char *, int );
+#endif
+
 #endif /* MBEDTLS_ERROR_C || MBEDTLS_ERROR_STRERROR_DUMMY */