diff --git a/programs/test/selftest.c b/programs/test/selftest.c
index 9bc9a9c6..fe35bb15 100644
--- a/programs/test/selftest.c
+++ b/programs/test/selftest.c
@@ -185,7 +185,7 @@ 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 ca51e7b2..1178135c 100644
--- a/tests/suites/host_test.function
+++ b/tests/suites/host_test.function
@@ -330,7 +330,7 @@ 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";