curl_getdate.3 5.0 KB

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  8. .\" * Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
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  24. a.TH curl_getdate 3 "12 Aug 2005" "libcurl" "libcurl"
  25. .SH NAME
  26. curl_getdate - Convert a date string to number of seconds
  27. .SH SYNOPSIS
  28. .nf
  29. #include <curl/curl.h>
  30. time_t curl_getdate(char *datestring, time_t *now);
  31. .fi
  32. .SH DESCRIPTION
  33. \fIcurl_getdate(3)\fP returns the number of seconds since the Epoch, January
  34. 1st 1970 00:00:00 in the UTC time zone, for the date and time that the
  35. \fIdatestring\fP parameter specifies. The \fInow\fP parameter is not used,
  36. pass a NULL there.
  37. This function works with valid dates and does not always detect and reject
  38. wrong dates, such as February 30.
  39. .SH PARSING DATES AND TIMES
  40. A "date" is a string containing several items separated by whitespace. The
  41. order of the items is immaterial. A date string may contain many flavors of
  42. items:
  43. .TP 0.8i
  44. .B calendar date items
  45. Can be specified several ways. Month names can only be three-letter English
  46. abbreviations, numbers can be zero-prefixed and the year may use 2 or 4
  47. digits. Examples: 06 Nov 1994, 06-Nov-94 and Nov-94 6.
  48. .TP
  49. .B time of the day items
  50. This string specifies the time on a given day. You must specify it with 6
  51. digits with two colons: HH:MM:SS. If there is no time given in a provided date
  52. string, 00:00:00 is assumed. Example: 18:19:21.
  53. .TP
  54. .B time zone items
  55. Specifies international time zone. There are a few acronyms supported, but in
  56. general you should instead use the specific relative time compared to
  57. UTC. Supported formats include: -1200, MST, +0100.
  58. .TP
  59. .B day of the week items
  60. Specifies a day of the week. Days of the week may be spelled out in full
  61. (using English): `Sunday', `Monday', etc or they may be abbreviated to their
  62. first three letters. This is usually not info that adds anything.
  63. .TP
  64. .B pure numbers
  65. If a decimal number of the form YYYYMMDD appears, then YYYY is read as the
  66. year, MM as the month number and DD as the day of the month, for the specified
  67. calendar date.
  68. .SH EXAMPLE
  69. .nf
  70. time_t t;
  71. t = curl_getdate("Sun, 06 Nov 1994 08:49:37 GMT", NULL);
  72. t = curl_getdate("Sunday, 06-Nov-94 08:49:37 GMT", NULL);
  73. t = curl_getdate("Sun Nov 6 08:49:37 1994", NULL);
  74. t = curl_getdate("06 Nov 1994 08:49:37 GMT", NULL);
  75. t = curl_getdate("06-Nov-94 08:49:37 GMT", NULL);
  76. t = curl_getdate("Nov 6 08:49:37 1994", NULL);
  77. t = curl_getdate("06 Nov 1994 08:49:37", NULL);
  78. t = curl_getdate("06-Nov-94 08:49:37", NULL);
  79. t = curl_getdate("1994 Nov 6 08:49:37", NULL);
  80. t = curl_getdate("GMT 08:49:37 06-Nov-94 Sunday", NULL);
  81. t = curl_getdate("94 6 Nov 08:49:37", NULL);
  82. t = curl_getdate("1994 Nov 6", NULL);
  83. t = curl_getdate("06-Nov-94", NULL);
  84. t = curl_getdate("Sun Nov 6 94", NULL);
  85. t = curl_getdate("1994.Nov.6", NULL);
  86. t = curl_getdate("Sun/Nov/6/94/GMT", NULL);
  87. t = curl_getdate("Sun, 06 Nov 1994 08:49:37 CET", NULL);
  88. t = curl_getdate("06 Nov 1994 08:49:37 EST", NULL);
  89. t = curl_getdate("Sun, 12 Sep 2004 15:05:58 -0700", NULL);
  90. t = curl_getdate("Sat, 11 Sep 2004 21:32:11 +0200", NULL);
  91. t = curl_getdate("20040912 15:05:58 -0700", NULL);
  92. t = curl_getdate("20040911 +0200", NULL);
  93. .fi
  94. .SH STANDARDS
  95. This parser handles date formats specified in RFC 822 (including the update in
  96. RFC 1123) using time zone name or time zone delta and RFC 850 (obsoleted by
  97. RFC 1036) and ANSI C's \fIasctime()\fP format.
  98. These formats are the only ones RFC 7231 says HTTP applications may use.
  99. .SH AVAILABILITY
  100. Always
  101. .SH RETURN VALUE
  102. This function returns -1 when it fails to parse the date string. Otherwise it
  103. returns the number of seconds as described.
  104. On systems with a signed 32 bit time_t: if the year is larger than 2037 or
  105. less than 1903, this function returns -1.
  106. On systems with an unsigned 32 bit time_t: if the year is larger than 2106 or
  107. less than 1970, this function returns -1.
  108. On systems with 64 bit time_t: if the year is less than 1583, this function
  109. returns -1. (The Gregorian calendar was first introduced 1582 so no "real"
  110. dates in this way of doing dates existed before then.)
  111. .SH "SEE ALSO"
  112. .BR curl_easy_escape "(3), " curl_easy_unescape "(3), "
  113. .BR CURLOPT_TIMECONDITION "(3), " CURLOPT_TIMEVALUE "(3) "