reasons, this call is restricted to the superuser. If FILENAME is
omitted, does a C<chroot> to C<$_>.
+B<NOTE:> It is good security practice to do C<chdir("/")> (to the root
+directory) immediately after a C<chroot()>.
+
Portability issues: L<perlport/chroot>.
=item close FILEHANDLE
delete() may also be used on arrays and array slices, but its behavior is less
straightforward. Although exists() will return false for deleted entries,
deleting array elements never changes indices of existing values; use shift()
-or splice() for that. However, if all deleted elements fall at the end of an
+or splice() for that. However, if any deleted elements fall at the end of an
array, the array's size shrinks to the position of the highest element that
-still tests true for exists(), or to 0 if none do.
+still tests true for exists(), or to 0 if none do. In other words, an
+array won't have trailing nonexistent elements after a delete.
B<WARNING:> Calling delete on array values is deprecated and likely to
be removed in a future version of Perl.
C<keys> or C<values> on the hash or array. If you add or delete a hash's
elements while iterating over it, the effect on the iterator is
unspecified; for example, entries may be skipped or duplicated--so don't
-do that. Exception: In the current implementation, it is always safe to
-delete the item most recently returned by C<each()>, so the following code
-works properly:
+do that. Exception: It is always safe to delete the item most recently
+returned by C<each()>, so the following code works properly:
while (($key, $value) = each %hash) {
print $key, "\n";
warnings to STDERR, nor does it stuff the text of warning messages into C<$@>.
To do either of those, you have to use the C<$SIG{__WARN__}> facility, or
turn off warnings inside the BLOCK or EXPR using S<C<no warnings 'all'>>.
-See L</warn>, L<perlvar>, L<warnings> and L<perllexwarn>.
+See L</warn>, L<perlvar>, and L<warnings>.
Note that, because C<eval> traps otherwise-fatal errors, it is useful for
determining whether a particular feature (such as C<socket> or C<symlink>)
system C library. In list context, the return values from the
various get routines are as follows:
- ($name,$passwd,$uid,$gid,
- $quota,$comment,$gcos,$dir,$shell,$expire) = getpw*
- ($name,$passwd,$gid,$members) = getgr*
- ($name,$aliases,$addrtype,$length,@addrs) = gethost*
- ($name,$aliases,$addrtype,$net) = getnet*
- ($name,$aliases,$proto) = getproto*
- ($name,$aliases,$port,$proto) = getserv*
+ # 0 1 2 3 4
+ ( $name, $passwd, $gid, $members ) = getgr*
+ ( $name, $aliases, $addrtype, $net ) = getnet*
+ ( $name, $aliases, $port, $proto ) = getserv*
+ ( $name, $aliases, $proto ) = getproto*
+ ( $name, $aliases, $addrtype, $length, @addrs ) = gethost*
+ ( $name, $passwd, $uid, $gid, $quota,
+ $comment, $gcos, $dir, $shell, $expire ) = getpw*
+ # 5 6 7 8 9
(If the entry doesn't exist you get an empty list.)
=for Pod::Functions send a signal to a process or process group
-Sends a signal to a list of processes. Returns the number of
-processes successfully signaled (which is not necessarily the
-same as the number actually killed).
+Sends a signal to a list of processes. Returns the number of arguments
+that were successfully used to signal (which is not necessarily the same
+as the number of processes actually killed, e.g. where a process group is
+killed).
$cnt = kill 'HUP', $child1, $child2;
kill 'KILL', @goners;
See L<perlipc/"Signals"> for more details.
-On some platforms such as Windows where the fork() system call is not available.
-Perl can be built to emulate fork() at the interpreter level.
+On some platforms such as Windows where the fork() system call is not
+available, Perl can be built to emulate fork() at the interpreter level.
This emulation has limitations related to kill that have to be considered,
for code running on Windows and in code intended to be portable.
=item If C<use bytes> is in effect:
-The results follow ASCII semantics. Only characters C<A-Z> change, to C<a-z>
-respectively.
+The results follow ASCII rules. Only the characters C<A-Z> change,
+to C<a-z> respectively.
=item Otherwise, if C<use locale> (but not C<use locale ':not_characters'>) is in effect:
Respects current LC_CTYPE locale for code points < 256; and uses Unicode
-semantics for the remaining code points (this last can only happen if
+rules for the remaining code points (this last can only happen if
the UTF8 flag is also set). See L<perllocale>.
Starting in v5.20, Perl wil use full Unicode rules if the locale is
UTF-8. Otherwise, there is a deficiency in this scheme, which is that
case changes that cross the 255/256
boundary are not well-defined. For example, the lower case of LATIN CAPITAL
-LETTER SHARP S (U+1E9E) in Unicode semantics is U+00DF (on ASCII
+LETTER SHARP S (U+1E9E) in Unicode rules is U+00DF (on ASCII
platforms). But under C<use locale> (prior to v5.20 or not a UTF-8
locale), the lower case of U+1E9E is
itself, because 0xDF may not be LATIN SMALL LETTER SHARP S in the
=item Otherwise, If EXPR has the UTF8 flag set:
-Unicode semantics are used for the case change.
+Unicode rules are used for the case change.
=item Otherwise, if C<use feature 'unicode_strings'> or C<use locale ':not_characters'> is in effect:
-Unicode semantics are used for the case change.
+Unicode rules are used for the case change.
=item Otherwise:
-ASCII semantics are used for the case change. The lowercase of any character
+ASCII rules are used for the case change. The lowercase of any character
outside the ASCII range is the character itself.
=back
everyone happy.
To recursively create a directory structure, look at
-the C<mkpath> function of the L<File::Path> module.
+the C<make_path> function of the L<File::Path> module.
=item msgctl ID,CMD,ARG
X<msgctl>
https://perl5.git.perl.org / perl5.git / blobdiff