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std::gmtime(3) C++ Standard Libary std::gmtime(3) NAME std::gmtime - std::gmtime Synopsis Defined in header <ctime> std::tm* gmtime( const std::time_t* time ); Converts given time since epoch as std::time_t value into calendar time, expressed in Coordinated Universal Time (UTC). Parameters time - pointer to a time_t object to convert Return value Pointer to a static internal std::tm object on success, or null pointer otherwise. The structure may be shared between std::gmtime, std::localtime, and std::ctime and may be overwritten on each invocation. Notes This function may not be thread-safe. POSIX requires that this function sets errno to EOVERFLOW if it fails because the argument is too large. Example // Run this code #include <iostream> #include <sstream> #include <iomanip> #include <ctime> 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 London std::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 GMT local: Wed Jul 15 10:15:00 2020 BST See also localtime converts time since epoch to calendar time expressed as local time (function) http://cppreference.com 2022.07.31 std::gmtime(3)
NAME | Synopsis | Parameters | Return value | Notes | Example | Possible output: | See also
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