OPENSSL_gmtime.3ossl 3.8 KB

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  57. .IX Title "OPENSSL_GMTIME 3ossl"
  58. .TH OPENSSL_GMTIME 3ossl 2025-01-17 3.4.0 OpenSSL
  59. .\" For nroff, turn off justification. Always turn off hyphenation; it makes
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  61. .if n .ad l
  62. .nh
  63. .SH NAME
  64. OPENSSL_gmtime,
  65. OPENSSL_gmtime_adj,
  66. OPENSSL_gmtime_diff \- platform\-agnostic OpenSSL time routines
  67. .SH SYNOPSIS
  68. .IX Header "SYNOPSIS"
  69. .Vb 1
  70. \& #include <openssl/crypto.h>
  71. \&
  72. \& struct tm *OPENSSL_gmtime(const time_t *timer, struct tm *result);
  73. \& int OPENSSL_gmtime_adj(struct tm *tm, int offset_day, long offset_sec);
  74. \& int OPENSSL_gmtime_diff(int *pday, int *psec,
  75. \& const struct tm *from, const struct tm *to);
  76. .Ve
  77. .SH DESCRIPTION
  78. .IX Header "DESCRIPTION"
  79. \&\fBOPENSSL_gmtime()\fR returns the UTC time specified by \fItimer\fR into the provided
  80. \&\fIresult\fR argument.
  81. .PP
  82. \&\fBOPENSSL_gmtime_adj()\fR adds the offsets in \fIoffset_day\fR and \fIoffset_sec\fR to \fItm\fR.
  83. .PP
  84. \&\fBOPENSSL_gmtime_diff()\fR calculates the difference between \fIfrom\fR and \fIto\fR.
  85. .SH NOTES
  86. .IX Header "NOTES"
  87. It is an error to call \fBOPENSSL_gmtime()\fR with \fIresult\fR equal to NULL. The
  88. contents of the time_t given by \fItimer\fR are stored into the \fIresult\fR. Calling
  89. with \fItimer\fR equal to NULL means use the current time.
  90. .PP
  91. \&\fBOPENSSL_gmtime_adj()\fR converts \fItm\fR into a days and seconds value, adds the
  92. offsets, then converts back into a \fIstruct tm\fR specified by \fItm\fR. Leap seconds
  93. are not considered.
  94. .PP
  95. \&\fBOPENSSL_gmtime_diff()\fR calculates the difference between the two \fIstruct tm\fR
  96. structures \fIfrom\fR and \fIto\fR. The difference in days is placed into \fI*pday\fR,
  97. the remaining seconds are placed to \fI*psec\fR. The value in \fI*psec\fR will be less
  98. than the number of seconds per day (3600). Leap seconds are not considered.
  99. .SH "RETURN VALUES"
  100. .IX Header "RETURN VALUES"
  101. \&\fBOPENSSL_gmtime()\fR returns NULL on error, or \fIresult\fR on success.
  102. .PP
  103. \&\fBOPENSSL_gmtime_adj()\fR and \fBOPENSSL_gmtime_diff()\fR return 0 on error, and 1 on success.
  104. .SH HISTORY
  105. .IX Header "HISTORY"
  106. \&\fBOPENSSL_gmtime()\fR, \fBOPENSSL_gmtime_adj()\fR and \fBOPENSSL_gmtime_diff()\fR have been
  107. in OpenSSL since 1.0.0.
  108. .SH COPYRIGHT
  109. .IX Header "COPYRIGHT"
  110. Copyright 2022 The OpenSSL Project Authors. All Rights Reserved.
  111. .PP
  112. Licensed under the Apache License 2.0 (the "License"). You may not use
  113. this file except in compliance with the License. You can obtain a copy
  114. in the file LICENSE in the source distribution or at
  115. <https://www.openssl.org/source/license.html>.