diff --git a/src/ftdipp_mpsse.cpp b/src/ftdipp_mpsse.cpp
index 167b488..197114e 100644
--- a/src/ftdipp_mpsse.cpp
+++ b/src/ftdipp_mpsse.cpp
@@ -365,7 +365,7 @@ int FTDIpp_MPSSE::setClkFreq(uint32_t clkHZ)
 	}
 
 	if (_clkHZ > base_freq / 2) {
-		printWarn("Jtag probe limited to %d MHz", base_freq / 2);
+		printWarn("Jtag probe limited to %d MHz" + std::to_string(base_freq / 2));
 		_clkHZ = base_freq / 2;
 	}