diff --git a/include/maestro/core.h b/include/maestro/core.h
index 71e72f5e3fbbff0385939e6fe26575bad3f570d7..c22cad6a9e83eb98e79eb738ba9533a81f9f85c8 100644
--- a/include/maestro/core.h
+++ b/include/maestro/core.h
@@ -43,7 +43,8 @@ extern "C" {
   #include "maestro/config.h"
   #include "maestro/status.h"
   #include <stdint.h>
-
+  #include <inttypes.h>
+  
   /**@defgroup MSTRO_Core Maestro Core API
    **@{
    ** This is the core API, as developed for D3.2
@@ -96,7 +97,12 @@ extern "C" {
    ** Application-in-workflow identifier type
    **/
   typedef uint64_t mstro_app_id;
-  
+
+  /**
+   ** A printf format specifie suitable to print an @ref mstro_app_id value
+   **/
+  #define PRIappid PRIu64
+
   /**@} (end of group MSTRO_Core) */
   
   /* include the remaining public API */