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Defined in header <ctime> | ||
std::tm* gmtime(conststd::time_t* time); | ||
Converts given time since epoch asstd::time_t value into calendar time, expressed in Coordinated Universal Time (UTC).
Contents |
| time | - | pointer to a time_t object to convert |
Pointer to a static internalstd::tm object on success, or null pointer otherwise. The structure may be shared betweenstd::gmtime,std::localtime, andstd::ctime and may be overwritten on each invocation.
This function may not be thread-safe.
POSIX requires thatgmtime setserrno toEOVERFLOW if it fails because the argument is too large.
#include <ctime>#include <iomanip>#include <iostream>#include <sstream> int main(){ setenv("TZ","/usr/share/zoneinfo/Europe/London",1);// POSIX-specific std::tm tm{};// get_time does not set all fields hence {} tm.tm_year=2020-1900;// 2020 tm.tm_mon=7-1;// July tm.tm_mday=15;// 15th tm.tm_hour=10; tm.tm_min=15; tm.tm_isdst=1;// Daylight saving in Londonstd::time_t t=std::mktime(&tm); std::cout<<"UTC: "<<std::put_time(std::gmtime(&t),"%c %Z")<<'\n';std::cout<<"local: "<<std::put_time(std::localtime(&t),"%c %Z")<<'\n';}
Possible output:
UTC: Wed Jul 15 09:15:00 2020 GMTlocal: Wed Jul 15 10:15:00 2020 BST
| converts time since epoch to calendar time expressed as local time (function)[edit] | |
C documentation forgmtime | |
