mktime() 在 C 中覆盖 time_t

Question

我对 c:

中的 mktime 有疑问

time_t t_fim;
time(&t_fim);

struct tm* p_fim;
struct tm* c_fim;
p_fim = localtime(&t_fim);
c_fim = localtime(&t_fim);

......

p_fim->tm_year = ano-1900;
p_fim->tm_mon = mes-1;
p_fim->tm_mday = dia;
//here the p_fim date is good

c_fim->tm_mday -=47;
mktime(c_fim);

printf("Pascoa %d %d %d\n", p_fim->tm_mday, p_fim->tm_mon + 1, p_fim->tm_year + 1900);
printf("Carnaval %d %d %d\n", c_fim->tm_mday, c_fim->tm_mon+1, c_fim->tm_year + 1900);

//here the c_fim is good with -47 days but the `p_fim` is now equal with `c_fim`

mktime正在改变p_fim的值，如何解决？

Answer 1

尝试摆脱指针

struct tm p_fim;
struct tm c_fim;
p_fim = *localtime(&t_fim);
c_fim = *localtime(&t_fim);

或者，如果您使用的是 POSIX 系统，请尝试 localtime_r() 而不是

mktime() 在 C 中覆盖 time_t

mktime() overwrite time_t in C

c

mktime