Fix GUI template

templates/skeletons/gui-body/function.tmplt

@@ -38,9 +38,12 @@
 #include "@_LOWER:Name_@.h"
 #include "@_LOWER:Name_@_enums_def.h"
 
-@@IF@@ @_List_Of_ASync_PIs'Length_@ > 0
+//  @_List_Of_ASync_PIs_@
 typedef struct _PI_Messages {
+@@IF@@ @_List_Of_ASync_PIs'Length_@ > 1 or (@_List_Of_ASync_PIs'Length_@ = 1 and @_List_Of_ASync_RIs'Length_@ = 0)
+@@-- >1 means there is the Poll function, otherwise =1 if there are no RIs (no Poll function)
    T_@_LOWER:Name_@_PI_list msg_id;
+@@END_IF@@
    union {
       @@TABLE@@
       @@IF@@ @_ASync_PI_Param_Type_@ /= ""
@@ -49,13 +52,11 @@ typedef struct _PI_Messages {
       @@END_TABLE@@
    } msg_data;
 } PI_Messages;
-@@ELSE@@
-typedef bool PI_Messages;
-@@END_IF@@
 
-@@IF@@ @_List_Of_ASync_RIs'Length_@ > 1  @@-- 1 because we ignore Poll
 typedef struct _RI_Messages {
+@@IF@@ @_List_Of_ASync_RIs'Length_@ > 0
    T_@_LOWER:Name_@_RI_list msg_id;
+@@END_IF@@
    union {
       @@TABLE@@
       @@IF@@ @_ASync_RI_Param_Type_@ /= ""
@@ -64,9 +65,6 @@ typedef struct _RI_Messages {
       @@END_TABLE@@
    } msg_data;
 } RI_Messages;
-@@ELSE@@
-typedef bool RI_Messages;
-@@END_IF@@
 
 @@IF@@ @_List_Of_PIs'Length_@ > 0
 // Queues of messages going from the binary to the user (PIs, or TMs)