1=pod 2 3=head1 NAME 4 5OPENSSL_gmtime, 6OPENSSL_gmtime_adj, 7OPENSSL_gmtime_diff - platform-agnostic OpenSSL time routines 8 9=head1 SYNOPSIS 10 11 #include <openssl/crypto.h> 12 13 struct tm *OPENSSL_gmtime(const time_t *timer, struct tm *result); 14 int OPENSSL_gmtime_adj(struct tm *tm, int offset_day, long offset_sec); 15 int OPENSSL_gmtime_diff(int *pday, int *psec, 16 const struct tm *from, const struct tm *to); 17 18=head1 DESCRIPTION 19 20OPENSSL_gmtime() returns the UTC time specified by I<timer> into the provided 21I<result> argument. 22 23OPENSSL_gmtime_adj() adds the offsets in I<offset_day> and I<offset_sec> to I<tm>. 24 25OPENSSL_gmtime_diff() calculates the difference between I<from> and I<to>. 26 27=head1 NOTES 28 29It is an error to call OPENSSL_gmtime() with I<result> equal to NULL. The 30contents of the time_t given by I<timer> are stored into the I<result>. Calling 31with I<timer> equal to NULL means use the current time. 32 33OPENSSL_gmtime_adj() converts I<tm> into a days and seconds value, adds the 34offsets, then converts back into a I<struct tm> specified by I<tm>. Leap seconds 35are not considered. 36 37OPENSSL_gmtime_diff() calculates the difference between the two I<struct tm> 38structures I<from> and I<to>. The difference in days is placed into I<*pday>, 39the remaining seconds are placed to I<*psec>. The value in I<*psec> will be less 40than the number of seconds per day (3600). Leap seconds are not considered. 41 42=head1 RETURN VALUES 43 44OPENSSL_gmtime() returns NULL on error, or I<result> on success. 45 46OPENSSL_gmtime_adj() and OPENSSL_gmtime_diff() return 0 on error, and 1 on success. 47 48=head1 HISTORY 49 50OPENSSL_gmtime(), OPENSSL_gmtime_adj() and OPENSSL_gmtime_diff() have been 51in OpenSSL since 1.0.0. 52 53=head1 COPYRIGHT 54 55Copyright 2022 The OpenSSL Project Authors. All Rights Reserved. 56 57Licensed under the Apache License 2.0 (the "License"). You may not use 58this file except in compliance with the License. You can obtain a copy 59in the file LICENSE in the source distribution or at 60L<https://www.openssl.org/source/license.html>. 61 62=cut 63