diff --git a/programs/test/selftest.c b/programs/test/selftest.c
index 2aa379b1c..41d704073 100644
--- a/programs/test/selftest.c
+++ b/programs/test/selftest.c
@@ -158,7 +158,7 @@ static int calloc_self_test( int verbose )
 }
 #endif /* MBEDTLS_SELF_TEST */
 
-static int test_snprintf( size_t n, const char ref_buf[10], int ref_ret )
+static int test_snprintf( size_t n, const char *ref_buf, int ref_ret )
 {
     int ret;
     char buf[10] = "xxxxxxxxx";
diff --git a/tests/suites/host_test.function b/tests/suites/host_test.function
index db53e9784..872a3a43a 100644
--- a/tests/suites/host_test.function
+++ b/tests/suites/host_test.function
@@ -335,7 +335,7 @@ static int convert_params( size_t cnt , char ** params , int * int_params_store
 #if defined(__GNUC__)
 __attribute__((__noinline__))
 #endif
-static int test_snprintf( size_t n, const char ref_buf[10], int ref_ret )
+static int test_snprintf( size_t n, const char *ref_buf, int ref_ret )
 {
     int ret;
     char buf[10] = "xxxxxxxxx";