diff --git a/src/ifcconvert/IfcConvert.cpp b/src/ifcconvert/IfcConvert.cpp
index d6720e70f4..5fbb6f9f85 100644
--- a/src/ifcconvert/IfcConvert.cpp
+++ b/src/ifcconvert/IfcConvert.cpp
@@ -707,6 +707,7 @@ bool init_input_file(const std::string &filename, IfcParse::IfcFile &ifc_file, b
 #ifdef USE_MMAP
 	if (!ifc_file.Init(filename, mmap)) {
 #else
+	(void)mmap;
 	if (!ifc_file.Init(filename)) {
 #endif
         Logger::Error("Unable to parse input file '" + filename + "'");