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Diffstat (limited to 'manual/time.texi')
| -rw-r--r-- | manual/time.texi | 171 |
1 files changed, 114 insertions, 57 deletions
diff --git a/manual/time.texi b/manual/time.texi index 9da23fbfb3..18224a5520 100644 --- a/manual/time.texi +++ b/manual/time.texi @@ -465,33 +465,34 @@ contains at least the following members, which can appear in any order: @table @code @item int tm_sec This is the number of seconds after the minute, normally in the range -@code{0} to @code{59}. (The actual upper limit is @code{60}, to allow +@code{0} through @code{59}. (The actual upper limit is @code{60}, to allow for leap seconds if leap second support is available.) @cindex leap second @item int tm_min -This is the number of minutes after the hour, in the range @code{0} to +This is the number of minutes after the hour, in the range @code{0} through @code{59}. @item int tm_hour -This is the number of hours past midnight, in the range @code{0} to +This is the number of hours past midnight, in the range @code{0} through @code{23}. @item int tm_mday -This is the day of the month, in the range @code{1} to @code{31}. +This is the day of the month, in the range @code{1} through @code{31}. @item int tm_mon -This is the number of months since January, in the range @code{0} to +This is the number of months since January, in the range @code{0} through @code{11}. @item int tm_year This is the number of years since @code{1900}. @item int tm_wday -This is the number of days since Sunday, in the range @code{0} to @code{6}. +This is the number of days since Sunday, in the range @code{0} through +@code{6}. @item int tm_yday -This is the number of days since January 1, in the range @code{0} to +This is the number of days since January 1, in the range @code{0} through @code{365}. @item int tm_isdst @@ -617,6 +618,7 @@ does so. @xref{Time Zone Functions}. @comment time.h @comment ANSI +@comment POSIX.2 @deftypefun size_t strftime (char *@var{s}, size_t @var{size}, const char *@var{template}, const struct tm *@var{brokentime}) This function is similar to the @code{sprintf} function (@pxref{Formatted Input}), but the conversion specifications that can appear in the format @@ -626,9 +628,9 @@ time conversion (@pxref{Locales}). Ordinary characters appearing in the @var{template} are copied to the output string @var{s}; this can include multibyte character sequences. -Conversion specifiers are introduced by a @samp{%} character. Now can -follow an optional flag which can be one of the following. These flags -only affect the output of numbers: +Conversion specifiers are introduced by a @samp{%} character, followed +by an optional flag which can be one of the following. These flags, +which are GNU extensions, affect only the output of numbers: @table @code @item _ @@ -638,9 +640,31 @@ The number is padded with spaces. The number is not padded at all. @end table -The default action is to pad the number with zeros. Following to the -flag comes the format specifier. The whole @samp{%} sequence is -replaced in the output string as follows: +The default action is to pad the number with zeros to keep it a constant +width. Numbers that do not have a range indicated below are never +padded, since there is no natural width for them. + +An optional modifier can follow the optional flag. The modifiers, which +are POSIX.2 extensions, are: + +@table @code +@item E +Use the locale's alternate representation for date and time. This +modifier applies to the @code{%c}, @code{%C}, @code{%x}, @code{%X}, +@code{%y} and @code{%Y} format specifiers. In a Japanese locale, for +example, @code{%Ex} might yield a date format based on the Japanese +Emperors' reigns. + +@item O +Use the locale's alternate numeric symbols for numbers. This modifier +applies only to numeric format specifiers. +@end table + +A modifier is ignored if no alternate representation is available. + +The conversion specifier ends with a format specifier taken from the +following list. The whole @samp{%} sequence is replaced in the output +string as follows: @table @code @item %a @@ -659,19 +683,38 @@ The full month name according to the current locale. The preferred date and time representation for the current locale. @item %C -The century of the year. +The century of the year. This is equivalent to the greatest integer not +greater than the year divided by 100. + +This format is a POSIX.2 extension. @item %d -The day of the month as a decimal number (range @code{01} to @code{31}). +The day of the month as a decimal number (range @code{01} through @code{31}). @item %D The date using the format @code{%m/%d/%y}. -This format is a GNU extension. +This format is a POSIX.2 extension. -@item %d +@item %e The day of the month like with @code{%d}, but padded with blank (range -@code{ 1} to @code{31}). +@code{ 1} through @code{31}). + +This format is a POSIX.2 extension. + +@item %g +The year corresponding to the ISO week number, but without the century +(range @code{00} through @code{99}). This has the same format and value +as @code{%y}, except that if the ISO week number (see @code{%V}) belongs +to the previous or next year, that year is used instead. + +This format is a GNU extension. + +@item %G +The year corresponding to the ISO week number. This has the same format +and value as @code{%Y}, except that if the ISO week number (see +@code{%V}) belongs to the previous or next year, that year is used +instead. This format is a GNU extension. @@ -679,50 +722,51 @@ This format is a GNU extension. The abbreviated month name according to the current locale. The action is the same as for @code{%b}. -This format is a GNU extension. +This format is a POSIX.2 extension. @item %H -The hour as a decimal number, using a 24-hour clock (range @code{00} to +The hour as a decimal number, using a 24-hour clock (range @code{00} through @code{23}). @item %I -The hour as a decimal number, using a 12-hour clock (range @code{01} to +The hour as a decimal number, using a 12-hour clock (range @code{01} through @code{12}). @item %j -The day of the year as a decimal number (range @code{001} to @code{366}). +The day of the year as a decimal number (range @code{001} through @code{366}). @item %k The hour as a decimal number, using a 24-hour clock like @code{%H}, but -padded with blank (range @code{ 0} to @code{23}). +padded with blank (range @code{ 0} through @code{23}). This format is a GNU extension. @item %l The hour as a decimal number, using a 12-hour clock like @code{%I}, but -padded with blank (range @code{ 0} to @code{12}). +padded with blank (range @code{ 1} through @code{12}). This format is a GNU extension. @item %m -The month as a decimal number (range @code{01} to @code{12}). +The month as a decimal number (range @code{01} through @code{12}). @item %M -The minute as a decimal number. +The minute as a decimal number (range @code{00} through @code{59}). @item %n A single @samp{\n} (newline) character. -This format is a GNU extension. +This format is a POSIX.2 extension. @item %p -Either @samp{am} or @samp{pm}, according to the given time value; or the -corresponding strings for the current locale. +Either @samp{AM} or @samp{PM}, according to the given time value; or the +corresponding strings for the current locale. Noon is treated as +@samp{PM} and midnight as @samp{AM}. @item %r -The time in decinal numbers using the format @code{%I:%M:%S %p}. +The complete time using the AM/PM format of the current locale. -This format is a GNU extension. +This format is a POSIX.2 extension. @item %R The hour and minute in decimal numbers using the format @code{%H:%M}. @@ -730,47 +774,58 @@ The hour and minute in decimal numbers using the format @code{%H:%M}. This format is a GNU extension. @item %s -The seconds since the epoch, i.e., 1970-01-01 00:00:00 UTC. Note -that this value is the number of seconds between the epoch and the -current date as defined by the @code{localtime} system call. +The number of seconds since the epoch, i.e., since 1970-01-01 00:00:00 UTC. +Leap seconds are not counted unless leap second support is available. This format is a GNU extension. @item %S -The second as a decimal number. +The second as a decimal number (range @code{00} through @code{60}). @item %t A single @samp{\t} (tabulator) character. -This format is a GNU extension. +This format is a POSIX.2 extension. @item %T The time using decimal numbers using the format @code{%H:%M:%S}. -This format is a GNU extension. +This format is a POSIX.2 extension. + +@item %u +The day of the week as a decimal number (range @code{1} through +@code{7}), Monday being @code{1}. + +This format is a POSIX.2 extension. @item %U -The week number of the current year as a decimal number, starting with -the first Sunday as the first day of the first week. All days preceding -the first Sunday in the year are considered to be in week @code{0}. +The week number of the current year as a decimal number (range @code{00} +through @code{53}), starting with the first Sunday as the first day of +the first week. Days preceding the first Sunday in the year are +considered to be in week @code{00}. @item %V -The @w{ISO 8601:1988} week number as a decimal number (range @code{00} -to @code{53}). ISO weeks start with Monday and end with Sunday. Week -01 of a year is the first week which has the majority of its days in -that year; this is equivalent to the week containing the year's first -Thursday, and it is also equivalent to the week containing January 4. -Week 01 of a year can contain days from the previous year. The week -before week 01 of a year is the last week (52 or 53) of the previous -year even if it contains days from the new year. +The @w{ISO 8601:1988} week number as a decimal number (range @code{01} +through @code{53}). ISO weeks start with Monday and end with Sunday. +Week @code{01} of a year is the first week which has the majority of its +days in that year; this is equivalent to the week containing the year's +first Thursday, and it is also equivalent to the week containing January +4. Week @code{01} of a year can contain days from the previous year. +The week before week @code{01} of a year is the last week (@code{52} or +@code{53}) of the previous year even if it contains days from the new +year. + +This format is a POSIX.2 extension. @item %w -The day of the week as a decimal number, Sunday being @code{0}. +The day of the week as a decimal number (range @code{0} through +@code{6}), Sunday being @code{0}. @item %W -The week number of the current year as a decimal number, starting with -the first Monday as the first day of the first week. All days preceding -the first Monday in the year are considered to be in week @code{0}. +The week number of the current year as a decimal number (range @code{00} +through @code{53}), starting with the first Monday as the first day of +the first week. All days preceding the first Monday in the year are +considered to be in week @code{00}. @item %x The preferred date representation for the current locale, but without the @@ -780,20 +835,22 @@ time. The preferred time representation for the current locale, but with no date. @item %y -The year as a decimal number, but without a century (range @code{00} to -@code{99}). +The year without a century as a decimal number (range @code{00} through +@code{99}). This is equivalent to the year modulo 100. @item %Y -The year as a decimal number, including the century. +The year as a decimal number, using the Gregorian calendar. Years +before the year @code{1} are numbered @code{0}, @code{-1}, and so on. @item %z @w{RFC 822}/@w{ISO 8601:1988} style numeric time zone (e.g., @code{-0600} or @code{+0100}), or nothing if no time zone is determinable. +This format is a GNU extension. + @item %Z -The time zone or name or abbreviation (empty if the time zone can't be -determined). +The time zone abbreviation (empty if the time zone can't be determined). @item %% A literal @samp{%} character. |