curl_getdate.3 4.3 KB

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  1. .\" generated by cd2nroff 0.1 from curl_getdate.md
  2. .TH curl_getdate 3 "2025-01-17" libcurl
  3. .SH NAME
  4. curl_getdate \- convert date string to number of seconds
  5. .SH SYNOPSIS
  6. .nf
  7. #include <curl/curl.h>
  8. time_t curl_getdate(const char *datestring, const time_t *now);
  9. .fi
  10. .SH DESCRIPTION
  11. \fIcurl_getdate(3)\fP returns the number of seconds since the Epoch, January
  12. 1st 1970 00:00:00 in the UTC time zone, for the date and time that the
  13. \fIdatestring\fP parameter specifies. The \fInow\fP parameter is not used,
  14. pass a NULL there.
  15. This function works with valid dates and does not always detect and reject
  16. wrong dates, such as February 30.
  17. .SH PARSING DATES AND TIMES
  18. A "date" is a string containing several items separated by whitespace. The
  19. order of the items is immaterial. A date string may contain many flavors of
  20. items:
  21. .IP "calendar date items"
  22. Can be specified several ways. Month names can only be three\-letter English
  23. abbreviations, numbers can be zero\-prefixed and the year may use 2 or 4
  24. digits. Examples: 06 Nov 1994, 06\-Nov\-94 and Nov\-94 6.
  25. If the year appears to be below 100 (two\-digit), any year after 70 is assumed
  26. to be 1900 + the given year. All others are 2000 + the given year.
  27. .IP "time of the day items"
  28. This string specifies the time on a given day. You must specify it with 6
  29. digits with two colons: HH:MM:SS. If there is no time given in a provided date
  30. string, 00:00:00 is assumed. Example: 18:19:21.
  31. .IP "time zone items"
  32. Specifies international time zone. There are a few acronyms supported, but in
  33. general you should instead use the specific relative time compared to
  34. UTC. Supported formats include: \-1200, MST, +0100.
  35. .IP "day of the week items"
  36. Specifies a day of the week. Days of the week may be spelled out in full
  37. (using English): \(aqSunday\(aq, \(aqMonday\(aq, etc or they may be abbreviated to their
  38. first three letters. This is usually not info that adds anything.
  39. .IP "pure numbers"
  40. If a decimal number of the form YYYYMMDD appears, then YYYY is read as the
  41. year, MM as the month number and DD as the day of the month, for the specified
  42. calendar date.
  43. .SH PROTOCOLS
  44. This functionality affects all supported protocols
  45. .SH EXAMPLE
  46. .nf
  47. int main(void)
  48. {
  49. time_t t;
  50. t = curl_getdate("Sun, 06 Nov 1994 08:49:37 GMT", NULL);
  51. t = curl_getdate("Sunday, 06-Nov-94 08:49:37 GMT", NULL);
  52. t = curl_getdate("Sun Nov 6 08:49:37 1994", NULL);
  53. t = curl_getdate("06 Nov 1994 08:49:37 GMT", NULL);
  54. t = curl_getdate("06-Nov-94 08:49:37 GMT", NULL);
  55. t = curl_getdate("Nov 6 08:49:37 1994", NULL);
  56. t = curl_getdate("06 Nov 1994 08:49:37", NULL);
  57. t = curl_getdate("06-Nov-94 08:49:37", NULL);
  58. t = curl_getdate("1994 Nov 6 08:49:37", NULL);
  59. t = curl_getdate("GMT 08:49:37 06-Nov-94 Sunday", NULL);
  60. t = curl_getdate("94 6 Nov 08:49:37", NULL);
  61. t = curl_getdate("1994 Nov 6", NULL);
  62. t = curl_getdate("06-Nov-94", NULL);
  63. t = curl_getdate("Sun Nov 6 94", NULL);
  64. t = curl_getdate("1994.Nov.6", NULL);
  65. t = curl_getdate("Sun/Nov/6/94/GMT", NULL);
  66. t = curl_getdate("Sun, 06 Nov 1994 08:49:37 CET", NULL);
  67. t = curl_getdate("06 Nov 1994 08:49:37 EST", NULL);
  68. t = curl_getdate("Sun, 12 Sep 2004 15:05:58 -0700", NULL);
  69. t = curl_getdate("Sat, 11 Sep 2004 21:32:11 +0200", NULL);
  70. t = curl_getdate("20040912 15:05:58 -0700", NULL);
  71. t = curl_getdate("20040911 +0200", NULL);
  72. }
  73. .fi
  74. .SH STANDARDS
  75. This parser handles date formats specified in RFC 822 (including the update in
  76. RFC 1123) using time zone name or time zone delta and RFC 850 (obsoleted by
  77. RFC 1036) and ANSI C\(aqs \fIasctime()\fP format.
  78. These formats are the only ones RFC 7231 says HTTP applications may use.
  79. .SH AVAILABILITY
  80. Added in curl 7.1
  81. .SH RETURN VALUE
  82. This function returns \-1 when it fails to parse the date string. Otherwise it
  83. returns the number of seconds as described.
  84. On systems with a signed 32\-bit time_t: if the year is larger than 2037 or
  85. less than 1903, this function returns \-1.
  86. On systems with an unsigned 32\-bit time_t: if the year is larger than 2106 or
  87. less than 1970, this function returns \-1.
  88. On systems with 64\-bit time_t: if the year is less than 1583, this function
  89. returns \-1. (The Gregorian calendar was first introduced 1582 so no "real"
  90. dates in this way of doing dates existed before then.)
  91. .SH SEE ALSO
  92. .BR CURLOPT_TIMECONDITION (3),
  93. .BR CURLOPT_TIMEVALUE (3),
  94. .BR curl_easy_escape (3),
  95. .BR curl_easy_unescape (3)