diff --git a/fft.h b/fft.h
index 80b559b..d24bbae 100644
--- a/fft.h
+++ b/fft.h
@@ -4,6 +4,7 @@
 #include <complex>
 #include <vector>
 #include <cmath>
+#include <cstring>
 
 #if defined(__FAST_MATH__) && (__apple_build_version__ >= 16000000) && (__apple_build_version__ <= 16000099) && !defined(SIGNALSMITH_IGNORE_BROKEN_APPLECLANG)
 #	error Apple Clang 16.0.0 generates incorrect SIMD for ARM. If you HAVE to use this version of Clang, turn off -ffast-math.