diff --git a/source/io/FileIO.cpp b/source/io/FileIO.cpp
index b2a423fed..3eab216ea 100644
--- a/source/io/FileIO.cpp
+++ b/source/io/FileIO.cpp
@@ -391,17 +391,26 @@ VIREO_FUNCTION_SIGNATURE2(Println, StaticType, void)
 }
 #endif
 //------------------------------------------------------------
-// An instruction to enable the Write to System Log VI which uses an SLI call to SystemLogging_WriteMessageUTF8
-// ignored(0), ignored(1), message(2), severity(3), error cluster(4)
 #if kVireoOS_emscripten
-VIREO_FUNCTION_SIGNATURE5(SystemLogging_WriteMessageUTF8, StringRef, StringRef, StringRef, Int32, ErrorCluster)
+struct SystemLogging_WriteMessageUTF8ParamBlock : InstructionCore
+{
+    _ParamDef(StringRef, Ignored0In);
+    _ParamDef(StringRef, Ignored1In);
+    _ParamDef(StringRef, MessageIn);
+    _ParamDef(Int32, SeverityIn);
+    _ParamDef(ErrorCluster, ErrorInOut);
+    NEXT_INSTRUCTION_METHOD()
+};
+
+// An instruction to enable the Write to System Log VI which uses an SLI call to SystemLogging_WriteMessageUTF8
+VIREO_FUNCTION_SIGNATURET(SystemLogging_WriteMessageUTF8, SystemLogging_WriteMessageUTF8ParamBlock)
 {
     TypeRef typeRefInt32 = TypeManagerScope::Current()->FindType("Int32");
 
-    if (!_Param(4).status) {
+    if (!_Param(ErrorInOut).status) {
         jsSystemLogging_WriteMessageUTF8(
-            _Param(2)->Type(), _ParamPointer(2),
-            typeRefInt32, _ParamPointer(3));
+            _Param(MessageIn)->Type(), _ParamPointer(MessageIn),
+            typeRefInt32, _ParamPointer(SeverityIn));
     }
     return _NextInstruction();
 }