diff --git a/c/common/shared_dictionary.c b/c/common/shared_dictionary.c
index 20ba73a..dc29110 100644
--- a/c/common/shared_dictionary.c
+++ b/c/common/shared_dictionary.c
@@ -460,7 +460,7 @@
 
 BROTLI_BOOL BrotliSharedDictionaryAttach(
     BrotliSharedDictionary* dict, BrotliSharedDictionaryType type,
-    size_t data_size, const uint8_t* data) {
+    size_t data_size, const uint8_t data[BROTLI_ARRAY_PARAM(data_size)]) {
   if (!dict) {
     return BROTLI_FALSE;
   }
diff --git a/c/dec/decode.c b/c/dec/decode.c
index 7370daa..e7e14fb 100644
--- a/c/dec/decode.c
+++ b/c/dec/decode.c
@@ -1494,8 +1494,9 @@
   return pos - orig_pos;
 }
 
-BROTLI_BOOL BrotliDecoderAttachDictionary(BrotliDecoderState* state,
-    BrotliSharedDictionaryType type, size_t data_size, const uint8_t* data) {
+BROTLI_BOOL BrotliDecoderAttachDictionary(
+    BrotliDecoderState* state, BrotliSharedDictionaryType type,
+    size_t data_size, const uint8_t data[BROTLI_ARRAY_PARAM(data_size)]) {
   uint32_t i;
   uint32_t num_prefix_before = state->dictionary->num_prefix;
   if (state->state != BROTLI_STATE_UNINITED) return BROTLI_FALSE;
diff --git a/c/enc/encode.c b/c/enc/encode.c
index 3076e66..dee6ee8 100644
--- a/c/enc/encode.c
+++ b/c/enc/encode.c
@@ -1974,8 +1974,8 @@
 }
 
 BrotliEncoderPreparedDictionary* BrotliEncoderPrepareDictionary(
-    BrotliSharedDictionaryType type, size_t size, const uint8_t* data,
-    int quality,
+    BrotliSharedDictionaryType type, size_t size,
+    const uint8_t data[BROTLI_ARRAY_PARAM(size)], int quality,
     brotli_alloc_func alloc_func, brotli_free_func free_func, void* opaque) {
   ManagedDictionary* managed_dictionary = NULL;
   if (type != BROTLI_SHARED_DICTIONARY_RAW &&