X<perl5>
C<abs>, C<bless>, C<chomp>, C<chr>, C<exists>, C<formline>, C<glob>,
-C<import>, C<lc>, C<lcfirst>, C<map>, C<my>, C<no>, C<our>, C<prototype>,
-C<qx>, C<qw>, C<readline>, C<readpipe>, C<ref>, C<sub*>, C<sysopen>, C<tie>,
-C<tied>, C<uc>, C<ucfirst>, C<untie>, C<use>
+C<import>, C<lc>, C<lcfirst>, C<lock>, C<map>, C<my>, C<no>, C<our>,
+C<prototype>, C<qr>, C<qw>, C<qx>, C<readline>, C<readpipe>, C<ref>,
+C<sub>*, C<sysopen>, C<tie>, C<tied>, C<uc>, C<ucfirst>, C<untie>, C<use>
* - C<sub> was a keyword in perl4, but in perl5 it is an
operator, which can be used in expressions.
On systems that support fchmod, you might pass file handles among the
files. On systems that don't support fchmod, passing file handles
-produces a fatal error at run time.
+produces a fatal error at run time. The file handles must be passed
+as globs or references to be recognized. Barewords are considered
+file names.
open(my $fh, "<", "foo");
my $perm = (stat $fh)[2] & 07777;
On systems that support fchown, you might pass file handles among the
files. On systems that don't support fchown, passing file handles
-produces a fatal error at run time.
+produces a fatal error at run time. The file handles must be passed
+as globs or references to be recognized. Barewords are considered
+file names.
Here's an example that looks up nonnumeric uids in the passwd file:
$cnt = kill 1, $child1, $child2;
kill 9, @goners;
-If SIGNAL is zero, no signal is sent to the process. This is a
-useful way to check that a child process is alive and hasn't changed
-its UID. See L<perlport> for notes on the portability of this
-construct.
+If SIGNAL is zero, no signal is sent to the process, but the kill(2)
+system call will check whether it's possible to send a signal to it (that
+means, to be brief, that the process is owned by the same user, or we are
+the super-user). This is a useful way to check that a child process is
+alive and hasn't changed its UID. See L<perlport> for notes on the
+portability of this construct.
Unlike in the shell, if SIGNAL is negative, it kills
process groups instead of processes. (On System V, a negative I<PROCESS>
open(FH, "<:utf8", "file")
will open the UTF-8 encoded file containing Unicode characters,
-see L<perluniintro>. (Note that if layers are specified in the
-three-arg form then default layers set by the C<open> pragma are
-ignored.)
+see L<perluniintro>. Note that if layers are specified in the
+three-arg form then default layers stored in ${^OPEN} (see L<perlvar>;
+usually set by the B<open> pragma or the switch B<-CioD>) are ignored.
Open returns nonzero upon success, the undefined value otherwise. If
the C<open> involved a pipe, the return value happens to be the pid of
L<perlsub/"Private Variables via my()"> for details, and L<fields>,
L<attributes>, and L<Attribute::Handlers>.
-The only currently recognized C<our()> attribute is C<unique> which
-indicates that a single copy of the global is to be used by all
-interpreters should the program happen to be running in a
-multi-interpreter environment. (The default behaviour would be for
-each interpreter to have its own copy of the global.) Examples:
-
- our @EXPORT : unique = qw(foo);
- our %EXPORT_TAGS : unique = (bar => [qw(aa bb cc)]);
- our $VERSION : unique = "1.00";
-
-Note that this attribute also has the effect of making the global
-readonly when the first new interpreter is cloned (for example,
-when the first new thread is created).
-
-Multi-interpreter environments can come to being either through the
-fork() emulation on Windows platforms, or by embedding perl in a
-multi-threaded application. The C<unique> attribute does nothing in
-all other environments.
-
-Warning: the current implementation of this attribute operates on the
-typeglob associated with the variable; this means that C<our $x : unique>
-also has the effect of C<our @x : unique; our %x : unique>. This may be
-subject to change.
-
=item pack TEMPLATE,LIST
X<pack>
I A unsigned integer value.
(This 'integer' is _at_least_ 32 bits wide. Its exact
size depends on what a local C compiler calls 'int'.)
-
+
n An unsigned short (16-bit) in "network" (big-endian) order.
N An unsigned long (32-bit) in "network" (big-endian) order.
v An unsigned short (16-bit) in "VAX" (little-endian) order.
eval "require $class";
-Now that you understand how C<require> looks for files in the case of
-a bareword argument, there is a little extra functionality going on
-behind the scenes. Before C<require> looks for a "F<.pm>" extension,
-it will first look for a filename with a "F<.pmc>" extension. A file
-with this extension is assumed to be Perl bytecode generated by
-L<B::Bytecode|B::Bytecode>. If this file is found, and its modification
-time is newer than a coinciding "F<.pm>" non-compiled file, it will be
-loaded in place of that non-compiled file ending in a "F<.pm>" extension.
+Now that you understand how C<require> looks for files in the case of a
+bareword argument, there is a little extra functionality going on behind
+the scenes. Before C<require> looks for a "F<.pm>" extension, it will
+first look for a similar filename with a "F<.pmc>" extension. If this file
+is found, it will be loaded in place of any file ending in a "F<.pm>"
+extension.
You can also insert hooks into the import facility, by putting directly
Perl code into the @INC array. There are three forms of hooks: subroutine
=item rindex STR,SUBSTR
-Works just like index() except that it returns the position of the LAST
+Works just like index() except that it returns the position of the I<last>
occurrence of SUBSTR in STR. If POSITION is specified, returns the
-last occurrence at or before that position.
+last occurrence beginning at or before that position.
=item rmdir FILENAME
X<rmdir> X<rd> X<directory, remove>
# File types. Not necessarily all are available on your system.
- S_IFREG S_IFDIR S_IFLNK S_IFBLK S_ISCHR S_IFIFO S_IFSOCK S_IFWHT S_ENFMT
+ S_IFREG S_IFDIR S_IFLNK S_IFBLK S_IFCHR S_IFIFO S_IFSOCK S_IFWHT S_ENFMT
# The following are compatibility aliases for S_IRUSR, S_IWUSR, S_IXUSR.
The behavior is undefined if LENGTH is greater than the length of the
file.
+The position in the file of FILEHANDLE is left unchanged. You may want to
+call L<seek> before writing to the file.
+
=item uc EXPR
X<uc> X<uppercase> X<toupper>
unlink @goners;
unlink <*.bak>;
-Note: C<unlink> will not delete directories unless you are superuser and
-the B<-U> flag is supplied to Perl. Even if these conditions are
+Note: C<unlink> will not attempt to delete directories unless you are superuser
+and the B<-U> flag is supplied to Perl. Even if these conditions are
met, be warned that unlinking a directory can inflict damage on your
-filesystem. Use C<rmdir> instead.
+filesystem. Finally, using C<unlink> on directories is not supported on
+many operating systems. Use C<rmdir> instead.
If LIST is omitted, uses C<$_>.
On systems that support futimes, you might pass file handles among the
files. On systems that don't support futimes, passing file handles
-produces a fatal error at run time.
+produces a fatal error at run time. The file handles must be passed
+as globs or references to be recognized. Barewords are considered
+file names.
=item values HASH
X<values>
projects / p5sagit/p5-mst-13.2.git / blobdiff