PROLOG<\/a> This manual page is part of the POSIX Programmer\u2019s Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.<\/p>\n localtime, localtime_r \u2014 convert a time value to a broken-down local time<\/p>\n #include struct tm *localtime(const time_t *timer<\/i>); For localtime<\/i>(): The functionality described on this reference page is aligned with the ISO\u00a0C standard. Any conflict between the requirements described here and the ISO\u00a0C standard is unintentional. This volume of POSIX.1-2017 defers to the ISO\u00a0C standard.<\/p>\n The localtime<\/i>() function shall convert the time in seconds since the Epoch pointed to by timer<\/i> into a broken-down time, expressed as a local time. The function corrects for the timezone and any seasonal time adjustments. Local timezone information is used as though localtime<\/i>() calls tzset<\/i>().<\/p>\n The relationship between a time in seconds since the Epoch used as an argument to localtime<\/i>() and the tm<\/b> structure (defined in the The same relationship shall apply for localtime_r<\/i>().<\/p>\n The localtime<\/i>() function need not be thread-safe.<\/p>\n The asctime<\/i>(), ctime<\/i>(), gmtime<\/i>(), and localtime<\/i>() functions shall return values in one of two static objects: a broken-down time structure and an array of type char<\/b>. Execution of any of the functions may overwrite the information returned in either of these objects by any of the other functions.<\/p>\n The localtime_r<\/i>() function shall convert the time in seconds since the Epoch pointed to by timer<\/i> into a broken-down time stored in the structure to which result<\/i> points. The localtime_r<\/i>() function shall also return a pointer to that same structure.<\/p>\n Unlike localtime<\/i>(), the localtime_r<\/i>() function is not required to set tzname<\/i>. If localtime_r<\/i>() sets tzname<\/i>, it shall also set daylight<\/i> and timezone<\/i>. If localtime_r<\/i>() does not set tzname<\/i>, it shall not set daylight<\/i> and shall not set timezone<\/i>.<\/p>\n Upon successful completion, the localtime<\/i>() function shall return a pointer to the broken-down time structure. If an error is detected, localtime<\/i>() shall return a null pointer and set errno<\/i> to indicate the error.<\/p>\n Upon successful completion, localtime_r<\/i>() shall return a pointer to the structure pointed to by the argument result<\/i>. If an error is detected, localtime_r<\/i>() shall return a null pointer and set errno<\/i> to indicate the error.<\/p>\n The localtime<\/i>() and localtime_r<\/i>() functions shall fail if: The result cannot be represented.<\/p>\n The following sections are informative.<\/i><\/p>\n Getting the Local Date and Time<\/b><\/i> #include int main(void) result = time(NULL); This example writes the current time to stdout<\/i> in a form like this:<\/p>\n Wed Jun 26 10:32:15 1996 Getting the Modification Time for a File<\/b> #include int if(stat(pathname, &statbuf) == -1) Timing an Event<\/b> #include The localtime_r<\/i>() function is thread-safe and returns values in a user-supplied buffer instead of possibly using a static data area that may be overwritten by each call.<\/p>\n None.<\/p>\n None.<\/p>\n asctime<\/i>(), clock<\/i>(), ctime<\/i>(), difftime<\/i>(), getdate<\/i>(), gmtime<\/i>(), mktime<\/i>(), strftime<\/i>(), strptime<\/i>(), time<\/i>(), tzset<\/i>(), utime<\/i>()<\/p>\n
NAME<\/a>
SYNOPSIS<\/a>
DESCRIPTION<\/a>
RETURN VALUE<\/a>
ERRORS<\/a>
EXAMPLES<\/a>
APPLICATION USAGE<\/a>
RATIONALE<\/a>
FUTURE DIRECTIONS<\/a>
SEE ALSO<\/a>
COPYRIGHT<\/a> <\/p>\n
\nPROLOG <\/a> <\/h2>\n
NAME <\/a> <\/h2>\n
SYNOPSIS <\/a> <\/h2>\n
struct tm *localtime_r(const time_t *restrict timer<\/i>,
struct tm *restrict result<\/i>);<\/p>\nDESCRIPTION <\/a> <\/h2>\n
RETURN VALUE <\/a> <\/h2>\n
ERRORS <\/a> <\/h2>\n
EOVERFLOW<\/b><\/p>\nEXAMPLES <\/a> <\/h2>\n
The following example uses the time<\/i>() function to calculate the time elapsed, in seconds, since January 1, 1970 0:00 UTC (the Epoch), localtime<\/i>() to convert that value to a broken-down time, and asctime<\/i>() to convert the broken-down time values into a printable string.<\/p>\n
#include
{
time_t result;<\/p>\n
printf(“%s%ju secs since the Epochn”,
asctime(localtime(&result)),
(uintmax_t)result);
return(0);
}<\/p>\n
835810335 secs since the Epoch<\/p>\n
The following example prints the last data modification timestamp in the local timezone for a given file.<\/p>\n
#include
#include
print_file_time(const char *pathname)
{
struct stat statbuf;
struct tm *tm;
char timestr[BUFSIZ];<\/p>\n
return -1;
if((tm = localtime(&statbuf.st_mtime)) == NULL)
return -1;
if(strftime(timestr, sizeof(timestr), “%Y-%m-%d %H:%M:%S”, tm) == 0)
return -1;
printf(“%s: %s.%09ldn”, pathname, timestr, statbuf.st_mtim.tv_nsec);
return 0;
}<\/p>\n
The following example gets the current time, converts it to a string using localtime<\/i>() and asctime<\/i>(), and prints it to standard output using fputs<\/i>(). It then prints the number of minutes to an event being timed.<\/p>\n
#include
…
time_t now;
int minutes_to_event;
…
time(&now);
printf(“The time is “);
fputs(asctime(localtime(&now)), stdout);
printf(“There are still %d minutes to the event.n”,
minutes_to_event);
…<\/p>\nAPPLICATION USAGE <\/a> <\/h2>\n
RATIONALE <\/a> <\/h2>\n
FUTURE DIRECTIONS <\/a> <\/h2>\n
SEE ALSO <\/a> <\/h2>\n