NAME

       OPENSSL_gmtime, OPENSSL_gmtime_adj, OPENSSL_gmtime_diff - platform-agnostic OpenSSL time
       routines

SYNOPSIS

        #include <openssl/crypto.h>

        struct tm *OPENSSL_gmtime(const time_t *timer, struct tm *result);
        int OPENSSL_gmtime_adj(struct tm *tm, int offset_day, long offset_sec);
        int OPENSSL_gmtime_diff(int *pday, int *psec,
                               const struct tm *from, const struct tm *to);

DESCRIPTION

       OPENSSL_gmtime() returns the UTC time specified by timer into the provided result
       argument.

       OPENSSL_gmtime_adj() adds the offsets in offset_day and offset_sec to tm.

       OPENSSL_gmtime_diff() calculates the difference between from and to.

NOTES

       It is an error to call OPENSSL_gmtime() with result equal to NULL. The contents of the
       time_t given by timer are stored into the result. Calling with timer equal to NULL means
       use the current time.

       OPENSSL_gmtime_adj() converts tm into a days and seconds value, adds the offsets, then
       converts back into a struct tm specified by tm. Leap seconds are not considered.

       OPENSSL_gmtime_diff() calculates the difference between the two struct tm structures from
       and to. The difference in days is placed into *pday, the remaining seconds are placed to
       *psec. The value in *psec will be less than the number of seconds per day (3600). Leap
       seconds are not considered.

RETURN VALUES

       OPENSSL_gmtime() returns NULL on error, or result on success.

       OPENSSL_gmtime_adj() and OPENSSL_gmtime_diff() return 0 on error, and 1 on success.

HISTORY

       OPENSSL_gmtime(), OPENSSL_gmtime_adj() and OPENSSL_gmtime_diff() have been in OpenSSL
       since 1.0.0.

COPYRIGHT

       Copyright 2022 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use this file except
       in compliance with the License.  You can obtain a copy in the file LICENSE in the source
       distribution or at <https://www.openssl.org/source/license.html>.