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OPENSSL_gmtime(3)                   OpenSSL                  OPENSSL_gmtime(3)



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

LIBRARY
       libcrypto, -lcrypto

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>.



3.0.12                            2023-05-07                 OPENSSL_gmtime(3)