Changes the permissions of a list of files. The first element of the
list must be the numerical mode, which should probably be an octal
-number, and which definitely should I<not> a string of octal digits:
+number, and which definitely should I<not> be a string of octal digits:
C<0644> is okay, C<'0644'> is not. Returns the number of files
successfully changed. See also L</oct>, if all you have is a string.
=item localtime EXPR
+=item localtime
+
Converts a time as returned by the time function to a 9-element list
with the time analyzed for the local time zone. Typically used as
follows:
# 0 1 2 3 4 5 6 7 8
($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) =
- localtime(time);
+ localtime(time);
All list elements are numeric, and come straight out of the C `struct
-tm'. $sec, $min, and $hour are the seconds, minutes, and hours of the
-specified time. $mday is the day of the month, and $mon is the month
-itself, in the range C<0..11> with 0 indicating January and 11
-indicating December. $year is the number of years since 1900. That
-is, $year is C<123> in year 2023. $wday is the day of the week, with
-0 indicating Sunday and 3 indicating Wednesday. $yday is the day of
-the year, in the range C<0..364> (or C<0..365> in leap years.) $isdst
-is true if the specified time occurs during daylight savings time,
-false otherwise.
+tm'. C<$sec>, C<$min>, and C<$hour> are the seconds, minutes, and hours
+of the specified time.
-Note that the $year element is I<not> simply the last two digits of
-the year. If you assume it is, then you create non-Y2K-compliant
-programs--and you wouldn't want to do that, would you?
+C<$mday> is the day of the month, and C<$mon> is the month itself, in
+the range C<0..11> with 0 indicating January and 11 indicating December.
+This makes it easy to get a month name from a list:
-The proper way to get a complete 4-digit year is simply:
+ my @abbr = qw( Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec );
+ print "$abbr[$mon] $mday";
+ # $mon=9, $mday=18 gives "Oct 18"
- $year += 1900;
+C<$year> is the number of years since 1900, not just the last two digits
+of the year. That is, C<$year> is C<123> in year 2023. The proper way
+to get a complete 4-digit year is simply:
-And to get the last two digits of the year (e.g., '01' in 2001) do:
+ $year += 1900;
- $year = sprintf("%02d", $year % 100);
+To get the last two digits of the year (e.g., '01' in 2001) do:
+
+ $year = sprintf("%02d", $year % 100);
+
+C<$wday> is the day of the week, with 0 indicating Sunday and 3 indicating
+Wednesday. C<$yday> is the day of the year, in the range C<0..364>
+(or C<0..365> in leap years.)
+
+C<$isdst> is true if the specified time occurs during Daylight Saving
+Time, false otherwise.
If EXPR is omitted, C<localtime()> uses the current time (C<localtime(time)>).
that would render sysseek() very slow).
sysseek() bypasses normal buffered IO, so mixing this with reads (other
-than C<sysread>, for example >< or read()) C<print>, C<write>,
+than C<sysread>, for example C<< <> >> or read()) C<print>, C<write>,
C<seek>, C<tell>, or C<eof> may cause confusion.
For WHENCE, you may also use the constants C<SEEK_SET>, C<SEEK_CUR>,
=item wantarray
Returns true if the context of the currently executing subroutine or
-eval() block is looking for a list value. Returns false if the context is
+C<eval> is looking for a list value. Returns false if the context is
looking for a scalar. Returns the undefined value if the context is
looking for no value (void context).
my @a = complex_calculation();
return wantarray ? @a : "@a";
+C<wantarray()>'s result is unspecified in the top level of a file,
+in a C<BEGIN>, C<CHECK>, C<INIT> or C<END> block, or in a C<DESTROY>
+method.
+
This function should have been named wantlist() instead.
=item warn LIST