diff --git a/scripts/data_files/error.fmt b/scripts/data_files/error.fmt
index b75a9ab..14522ec 100644
--- a/scripts/data_files/error.fmt
+++ b/scripts/data_files/error.fmt
@@ -20,7 +20,7 @@
 
 HEADER_INCLUDED
 
-const char *mbedtls_high_level_strerr(int error_code)
+static const char *mbedtls_high_level_strerr(int error_code)
 {
     int high_level_error_code;
 
@@ -43,7 +43,7 @@
     return NULL;
 }
 
-const char *mbedtls_low_level_strerr(int error_code)
+static const char *mbedtls_low_level_strerr(int error_code)
 {
     int low_level_error_code;