diff --git a/include/jemalloc/internal/size_classes.sh b/include/jemalloc/internal/size_classes.sh
index d8306a58..79b4ba23 100755
--- a/include/jemalloc/internal/size_classes.sh
+++ b/include/jemalloc/internal/size_classes.sh
@@ -13,7 +13,7 @@ lg_tmin=3
 lg_pmin=12
 lg_pmax=16
 
-function pow2() {
+pow2() {
   e=$1
   pow2_result=1
   while [ ${e} -gt 0 ] ; do