struct tm st1, st2 使用前沒有初始化

GNU 手冊上關於 strptime 提示寫到：

In principle, this function （strptime) does not initialize tm but only stores the values speci‐

fied. This means that tm should be initialized before the call. Details differ a

bit between different UNIX systems. The glibc implementation does not touch those

fields which are not explicitly specified, except that it recomputes the tm_wday and

tm_yday field if any of the year, month, or day elements changed.

time_t t1= 0;

errno = 0;

printf("%s\n", date);

+

+ memset( &st1, 0, sizeof( st1 ) );

+ memset( &st2, 0, sizeof( st2 ) );

+

if (NULL == strptime(date, "%Y%m%d", &st1))

{

perror("strptime error");

得到結果

20140228

__1393516800

20140301

20140301