diff --git a/include/ipmid/api.h b/include/ipmid/api.h
index f08ee11..188db4a 100644
--- a/include/ipmid/api.h
+++ b/include/ipmid/api.h
@@ -3,6 +3,8 @@
 
 #include <systemd/sd-bus.h>
 
+#include <cstddef>
+
 /*
  * Specifies the minimum privilege level required to execute the command
  * This means the command can be executed at a given privilege level or higher
@@ -53,7 +55,7 @@
 
 // Length of request / response buffer depending on whether the data is a
 // request or a response from a plugin handler.
-typedef size_t* ipmi_data_len_t;
+typedef std::size_t* ipmi_data_len_t;
 
 // Plugin function return the status code
 typedef unsigned char ipmi_ret_t;