diff --git a/c-programming/benchmarking/clock_hr_microsec.h b/c-programming/benchmarking/clock_hr_microsec.h
index a5c26f6..9eb8cc2 100644
--- a/c-programming/benchmarking/clock_hr_microsec.h
+++ b/c-programming/benchmarking/clock_hr_microsec.h
@@ -10,6 +10,7 @@
 #define _CLOCK_HR_MICROSEC_H
 
 #include <stdio.h>
+#include <time.h>
 
 // typedefs
 typedef long double clock_hr_microsec_t;