i don't know why both result same~

[Jung Seng Won]

#include <time.h> #include<stdio.h> #include <conio.h> #include <stdlib.h> #include <Windows.h> void main() { time_t curr, bir; struct tm *curr_tm, *bir_tm; curr = time(NULL); bir = time(NULL); curr_tm = localtime(&curr); bir_tm = localtime(&bir); // printf("%s\n", asctime(curr_tm)); // printf("%s\n", asctime(bir_tm)); bir_tm->tm_year = 83; bir_tm->tm_mon = 11; bir_tm->tm_mday = 26; printf("%s\n", asctime(curr_tm)); printf("%s\n", asctime(bir_tm)); }//main i don't know why printf("%s\n", asctime(curr_tm)); printf("%s\n", asctime(bir_tm)); 's result is same~ definitly curr_tm, bir_tm 's paramata is different~ example) curr_tm = localtime(&curr); bir_tm = localtime(&bir);

firstly, i am sorry, i am from korea. and i am not good in wriitting english so please understand~ Thank you everyone~

[Chris Losinger]

curr_tm = localtime(&curr); bir_tm = localtime(&bir); from the MSDN[^]: gmtime, mktime, and localtime all use a single statically allocated tm structure for the conversion. Each call to one of these routines destroys the result of the previous call. in other words, curr_tm and bir_tm have the same value because they are pointing at the same structure, because localtime returns the same structure each time you call it.

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[CPallini]

From localtime documentation [^] gmtime, mktime, and localtime all use a single statically allocated tm structure for the conversion. Each call to one of these routines destroys the result of the previous call. hence both curr_tm and bir_tm point to the same static struct. :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
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[CPallini]

Chris Losinger wrote:

gmtime, mktime, and localtime all use a single statically allocated tm structure for the conversion. Each call to one of these routines destroys the result of the previous call.

Though the assertion are in fact related, in the OP particular case, IMHO the

Chris Losinger wrote:

use a single statically allocated tm structure

is more relevant than

Chris Losinger wrote:

Each call to one of these routines destroys the result of the previous call

. :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
[my articles]