1NEWSTRFTIME(3) Library Functions Manual NEWSTRFTIME(3) 2 3NAME 4 strftime - format date and time 5 6SYNOPSIS 7 #include <time.h> 8 9 size_t strftime(char *restrict buf, size_t maxsize, 10 char const *restrict format, struct tm const *restrict timeptr); 11 12 cc ... -ltz 13 14DESCRIPTION 15 The strftime function formats the information from timeptr into the 16 array pointed to by buf according to the string pointed to by format. 17 18 The format string consists of zero or more conversion specifications 19 and ordinary characters. All ordinary characters are copied directly 20 into the array. A conversion specification consists of a percent sign 21 and one other character. 22 23 No more than maxsize bytes are placed into the array. 24 25 Each conversion specification is replaced by the characters as follows 26 which are then copied into the array. 27 28 %A is replaced by the locale's full weekday name. 29 30 %a is replaced by the locale's abbreviated weekday name. 31 32 %B is replaced by the locale's full month name. 33 34 %b or %h 35 is replaced by the locale's abbreviated month name. 36 37 %C is replaced by the century (a year divided by 100 and truncated 38 to an integer) as a decimal number [00,99]. 39 40 %c is replaced by the locale's appropriate date and time 41 representation. 42 43 %D is equivalent to %m/%d/%y. 44 45 %d is replaced by the day of the month as a decimal number [01,31]. 46 47 %e is replaced by the day of month as a decimal number [1,31]; 48 single digits are preceded by a blank. 49 50 %F is equivalent to %Y-%m-%d (the ISO 8601 date format). 51 52 %G is replaced by the ISO 8601 year with century as a decimal 53 number. See also the %V conversion specification. 54 55 %g is replaced by the ISO 8601 year without century as a decimal 56 number [00,99]. This is the year that includes the greater part 57 of the week. (Monday as the first day of a week). See also the 58 %V conversion specification. 59 60 %H is replaced by the hour (24-hour clock) as a decimal number 61 [00,23]. 62 63 %I is replaced by the hour (12-hour clock) as a decimal number 64 [01,12]. 65 66 %j is replaced by the day of the year as a decimal number 67 [001,366]. 68 69 %k is replaced by the hour (24-hour clock) as a decimal number 70 [0,23]; single digits are preceded by a blank. 71 72 %l is replaced by the hour (12-hour clock) as a decimal number 73 [1,12]; single digits are preceded by a blank. 74 75 %M is replaced by the minute as a decimal number [00,59]. 76 77 %m is replaced by the month as a decimal number [01,12]. 78 79 %n is replaced by a newline. 80 81 %p is replaced by the locale's equivalent of either "AM" or "PM". 82 83 %R is replaced by the time in the format %H:%M. 84 85 %r is replaced by the locale's representation of 12-hour clock time 86 using AM/PM notation. 87 88 %S is replaced by the second as a decimal number [00,60]. The 89 range of seconds is [00,60] instead of [00,59] to allow for the 90 periodic occurrence of leap seconds. 91 92 %s is replaced by the number of seconds since the Epoch (see 93 ctime(3)). 94 95 %T is replaced by the time in the format %H:%M:%S. 96 97 %t is replaced by a tab. 98 99 %U is replaced by the week number of the year (Sunday as the first 100 day of the week) as a decimal number [00,53]. 101 102 %u is replaced by the weekday (Monday as the first day of the week) 103 as a decimal number [1,7]. 104 105 %V is replaced by the week number of the year (Monday as the first 106 day of the week) as a decimal number [01,53]. If the week 107 containing January 1 has four or more days in the new year, then 108 it is week 1; otherwise it is week 53 of the previous year, and 109 the next week is week 1. The year is given by the %G conversion 110 specification. 111 112 %W is replaced by the week number of the year (Monday as the first 113 day of the week) as a decimal number [00,53]. 114 115 %w is replaced by the weekday (Sunday as the first day of the week) 116 as a decimal number [0,6]. 117 118 %X is replaced by the locale's appropriate time representation. 119 120 %x is replaced by the locale's appropriate date representation. 121 122 %Y is replaced by the year with century as a decimal number. 123 124 %y is replaced by the year without century as a decimal number 125 [00,99]. 126 127 %Z is replaced by the time zone abbreviation, or by the empty 128 string if this is not determinable. 129 130 %z is replaced by the offset from the Prime Meridian in the format 131 +HHMM or -HHMM (ISO 8601) as appropriate, with positive values 132 representing locations east of Greenwich, or by the empty string 133 if this is not determinable. The numeric time zone abbreviation 134 -0000 is used when the time is Universal Time but local time is 135 indeterminate; by convention this is used for locations while 136 uninhabited, and corresponds to a zero offset when the time zone 137 abbreviation begins with "-". 138 139 %% is replaced by a single %. 140 141 %+ is replaced by the locale's date and time in date(1) format. 142 143RETURN VALUE 144 If the conversion is successful, strftime returns the number of bytes 145 placed into the array, not counting the terminating NUL; errno is 146 unchanged if the returned value is zero. Otherwise, errno is set to 147 indicate the error, zero is returned, and the array contents are 148 unspecified. 149 150ERRORS 151 This function fails if: 152 153 [ERANGE] 154 The total number of resulting bytes, including the terminating 155 NUL character, is more than maxsize. 156 157 This function may fail if: 158 159 [EOVERFLOW] 160 The format includes an %s conversion and the number of seconds 161 since the Epoch cannot be represented in a time_t. 162 163SEE ALSO 164 date(1), getenv(3), newctime(3), newtzset(3), time(2), tzfile(5) 165 166BUGS 167 There is no conversion specification for the phase of the moon. 168 169 NEWSTRFTIME(3) 170