stdtime/strptime.3

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  26 .\" $FreeBSD: src/lib/libc/stdtime/strptime.3,v 1.9.2.7 2001/12/14 18:33:59 ru Exp $
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  28 .Dd May 8, 1997
  29 .Dt STRPTIME 3
  30 .Os
  31 .Sh NAME
  32 .Nm strptime
  33 .Nd parse date and time string
  34 .Sh LIBRARY
  35 .Lb libc
  36 .Sh SYNOPSIS
  37 .In time.h
  38 .Ft char *
  39 .Fn strptime "const char *buf" "const char *format" "struct tm *timeptr"
  40 .Sh DESCRIPTION
  41 The
  42 .Fn strptime
  43 function parses the string in the buffer
  44 .Fa buf
  45 according to the string pointed to by
  46 .Fa format ,
  47 and fills in the elements of the structure pointed to by
  48 .Fa timeptr .
  49 The resulting values will be relative to the local time zone.
  50 Thus, it can be considered the reverse operation of
  51 .Xr strftime 3 .
  52 .Pp
  53 The
  54 .Fa format
  55 string consists of zero or more conversion specifications and
  56 ordinary characters.
  57 All ordinary characters are matched exactly with the buffer, where
  58 white space in the format string will match any amount of white space
  59 in the buffer.
  60 All conversion specifications are identical to those described in
  61 .Xr strftime 3 .
  62 .Pp
  63 Two-digit year values, including formats
  64 .Fa %y
  65 and
  66 .Fa \&%D ,
  67 are now interpreted as beginning at 1969 per POSIX requirements.
  68 Years 69-00 are interpreted in the 20th century (1969-2000), years
  69 01-68 in the 21st century (2001-2068).
  70 .Sh RETURN VALUES
  71 Upon successful completion,
  72 .Fn strptime
  73 returns the pointer to the first character in
  74 .Fa buf
  75 that has not been required to satisfy the specified conversions in
  76 .Fa format .
  77 It returns
  78 .Dv NULL
  79 if one of the conversions failed.
  80 .Sh SEE ALSO
  81 .Xr date 1 ,
  82 .Xr scanf 3 ,
  83 .Xr strftime 3
  84 .Sh AUTHORS
  85 The
  86 .Fn strptime
  87 function has been contributed by Powerdog Industries.
  88 .Pp
  89 This man page was written by
  90 .An J\(:org Wunsch .
  91 .Sh HISTORY
  92 The
  93 .Fn strptime
  94 function appeared in
  95 .Fx 3.0 .
  96 .Sh BUGS
  97 Both the
  98 .Fa %e
  99 and
 100 .Fa %l
 101 format specifiers may incorrectly scan one too many digits
 102 if the intended values comprise only a single digit
 103 and that digit is followed immediately by another digit.
 104 Both specifiers accept zero-padded values,
 105 even though they are both defined as taking unpadded values.
 106 .Pp
 107 The
 108 .Fa %p
 109 format specifier has no effect unless it is parsed
 110 .Em after
 111 hour-related specifiers.
 112 Specifying
 113 .Fa %l
 114 without
 115 .Fa %p
 116 will produce undefined results.
 117 Note that 12AM
 118 (ante meridiem)
 119 is taken as midnight
 120 and 12PM
 121 (post meridiem)
 122 is taken as noon.
 123 .Pp
 124 The
 125 .Fa %U
 126 and
 127 .Fa %W
 128 format specifiers accept any value within the range 00 to 53
 129 without validating against other values supplied (like month
 130 or day of the year, for example).
 131 .Pp
 132 The
 133 .Fa %Z
 134 format specifier only accepts time zone abbreviations of the local time zone,
 135 or the value "GMT".
 136 This limitation is because of ambiguity due to of the over loading of time
 137 zone abbreviations.  One such example is
 138 .Fa EST
 139 which is both Eastern Standard Time and Eastern Australia Summer Time.