gistfile1.txt

diff --git a/datetime/timezone/timestamp.c b/datetime/timezone/timestamp.c
index 6ddb230..53a8857 100644
--- a/datetime/timezone/timestamp.c
+++ b/datetime/timezone/timestamp.c
@@ -31,7 +31,7 @@
 
 static int isdst_timestamp(time_t t);
 
-DSTTime*
+DSTTime
 get_dst_time(const char *zone, int year)
 {
 	register time_t		cutlotime;
@@ -47,11 +47,12 @@ get_dst_time(const char *zone, int year)
 	register struct tm *	tmp;
 	register struct tm *	newtmp;
 	static char	buf[MAX_STRING_LENGTH];
+	DSTTime ret = {0,0};
 
 	char *tz = getenv("TZ");
 	if (setenv("TZ", zone, 1) != 0 ) {
 		fprintf(stderr, "Set TZ=%s failed\n", zone);
-		return NULL;
+		return ret;
 	}
 
 	t = absolute_min_time;
@@ -63,11 +64,6 @@ get_dst_time(const char *zone, int year)
 		strncpy(buf, abbr(&tm), (sizeof buf) - 1);
 	}
 
-	DSTTime *ret = calloc(1, sizeof(DSTTime));
-	if (!ret) {
-		setenv("TZ", tz, 1);
-		return NULL;
-	}
 
 	int enter_flag = 0;
 	for ( ; ; ) {
@@ -88,17 +84,17 @@ get_dst_time(const char *zone, int year)
 			if (newtmp != NULL) {
 				if (newtmp->tm_isdst) {
 					if (!enter_flag) {
-						ret->enter = newt;
+						ret.enter = newt;
 						enter_flag = 1;
 					} else {
-						ret->leave = newt;
+						ret.leave = newt;
 					}
 				} else {
 					if (!enter_flag) {
-						ret->enter = newt-1;
+						ret.enter = newt-1;
 						enter_flag = 1;
 					} else {
-						ret->leave = newt-1;
+						ret.leave = newt-1;
 					}
 				}
 
diff --git a/datetime/timezone/timestamp.h b/datetime/timezone/timestamp.h
index 3623b54..af3b7ee 100644
--- a/datetime/timezone/timestamp.h
+++ b/datetime/timezone/timestamp.h
@@ -30,6 +30,6 @@ typedef struct _DSTTime {
 long long get_rawoffset_time (const char *zone, long long t);
 long long get_year_begin_time(const char *zone, int year);
 long getoffset (const char *zone, long long t);
-DSTTime* get_dst_time(const char *zone, int year);
+DSTTime get_dst_time(const char *zone, int year);
 
 #endif
diff --git a/datetime/timezone/wrapper.go b/datetime/timezone/wrapper.go
index c56b303..d5fd45c 100644
--- a/datetime/timezone/wrapper.go
+++ b/datetime/timezone/wrapper.go
@@ -35,13 +35,8 @@ func sumDSTTime(zone string, year int32) (int64, int64, bool) {
 	czone := C.CString(zone)
 	ret := C.get_dst_time(czone, C.int(year))
 
-	if ret == nil {
-		return 0, 0, false
-	}
-
 	t1 := int64(ret.enter)
 	t2 := int64(ret.leave)
-	C.free(unsafe.Pointer(ret))
 
 	if t1 == 0 || t2 == 0 {
 		return 0, 0, false