Update libbz3.h
diff --git a/include/libbz3.h b/include/libbz3.h
index 2912546..4cdc860 100644
--- a/include/libbz3.h
+++ b/include/libbz3.h
@@ -45,6 +45,7 @@ const char * bz3_strerror(struct bz3_state * state);
/**
* @brief Construct a new block encoder state, which will encode blocks as big as the given block size.
* The decoder will be able to decode blocks at most as big as the given block size.
+ * Returns NULL in case allocation fails.
*/
struct bz3_state * bz3_new(int32_t block_size);
