+#ifndef timerclear
+#define timerclear(tvp) ((tvp)->tv_sec = (tvp)->tv_usec = 0)
+#endif
+
+#ifndef timerisset
+#define timerisset(tvp) ((tvp)->tv_sec || (tvp)->tv_usec)
+#endif
+
+#ifndef timercmp
+#define timercmp(tvp, uvp, cmp) \
+ (((tvp)->tv_sec == (uvp)->tv_sec) ? \
+ ((tvp)->tv_usec cmp (uvp)->tv_usec) : \
+ ((tvp)->tv_sec cmp (uvp)->tv_sec))
+#endif
+
+#ifndef timeradd
+#define timeradd(tvp, uvp, vvp) \
+ do { \
+ (vvp)->tv_sec = (tvp)->tv_sec + (uvp)->tv_sec; \
+ (vvp)->tv_usec = (tvp)->tv_usec + (uvp)->tv_usec; \
+ if ((vvp)->tv_usec >= 1000000) { \
+ (vvp)->tv_sec++; \
+ (vvp)->tv_usec -= 1000000; \
+ } \
+ } while (0)
+#endif
+
+#ifndef timersub
+#define timersub(tvp, uvp, vvp) \
+ do { \
+ (vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec; \
+ (vvp)->tv_usec = (tvp)->tv_usec - (uvp)->tv_usec; \
+ if ((vvp)->tv_usec < 0) { \
+ (vvp)->tv_sec--; \
+ (vvp)->tv_usec += 1000000; \
+ } \
+ } while (0)
+#endif
+
+