L<C<fcntl>|/fcntl FILEHANDLE,FUNCTION,SCALAR>, L<C<glob>|/glob EXPR>,
L<C<ioctl>|/ioctl FILEHANDLE,FUNCTION,SCALAR>,
L<C<link>|/link OLDFILE,NEWFILE>, L<C<lstat>|/lstat FILEHANDLE>,
-L<C<mkdir>|/mkdir FILENAME,MASK>, L<C<open>|/open FILEHANDLE,EXPR>,
+L<C<mkdir>|/mkdir FILENAME,MODE>, L<C<open>|/open FILEHANDLE,EXPR>,
L<C<opendir>|/opendir DIRHANDLE,EXPR>, L<C<readlink>|/readlink EXPR>,
L<C<rename>|/rename OLDNAME,NEWNAME>, L<C<rmdir>|/rmdir FILENAME>,
L<C<select>|/select FILEHANDLE>, L<C<stat>|/stat FILEHANDLE>,
if (exists $ref->{"Some key"}) { }
print $ref; # prints HASH(0x80d3d5c)
-This surprising autovivification in what does not at first--or even
-second--glance appear to be an lvalue context may be fixed in a future
-release.
-
Use of a subroutine call, rather than a subroutine name, as an argument
to L<C<exists>|/exists EXPR> is an error.
to get a list of anonymous hashes each with only one entry apiece.
-=item mkdir FILENAME,MASK
+=item mkdir FILENAME,MODE
X<mkdir> X<md> X<directory, create>
=item mkdir FILENAME
=for Pod::Functions create a directory
Creates the directory specified by FILENAME, with permissions
-specified by MASK (as modified by L<C<umask>|/umask EXPR>). If it
+specified by MODE (as modified by L<C<umask>|/umask EXPR>). If it
succeeds it returns true; otherwise it returns false and sets
L<C<$!>|perlvar/$!> (errno).
-MASK defaults to 0777 if omitted, and FILENAME defaults
+MODE defaults to 0777 if omitted, and FILENAME defaults
to L<C<$_>|perlvar/$_> if omitted.
-In general, it is better to create directories with a permissive MASK
+In general, it is better to create directories with a permissive MODE
and let the user modify that with their L<C<umask>|/umask EXPR> than it
is to supply
-a restrictive MASK and give the user no way to be more permissive.
+a restrictive MODE and give the user no way to be more permissive.
The exceptions to this rule are when the file or directory should be
kept private (mail files, for instance). The documentation for
-L<C<umask>|/umask EXPR> discusses the choice of MASK in more detail.
+L<C<umask>|/umask EXPR> discusses the choice of MODE in more detail.
Note that according to the POSIX 1003.1-1996 the FILENAME may have any
number of trailing slashes. Some operating and filesystems do not get
Portability issues: L<perlport/socketpair>.
=item sort SUBNAME LIST
-X<sort> X<qsort> X<quicksort> X<mergesort>
+X<sort>
=item sort BLOCK LIST
actually modifies the element in the original list. This is usually
something to be avoided when writing clear code.
-Perl 5.6 and earlier used a quicksort algorithm to implement sort.
-That algorithm was not stable and I<could> go quadratic. (A I<stable> sort
-preserves the input order of elements that compare equal. Although
-quicksort's run time is O(NlogN) when averaged over all arrays of
-length N, the time can be O(N**2), I<quadratic> behavior, for some
-inputs.) In 5.7, the quicksort implementation was replaced with
-a stable mergesort algorithm whose worst-case behavior is O(NlogN).
-But benchmarks indicated that for some inputs, on some platforms,
-the original quicksort was faster. 5.8 has a L<sort> pragma for
-limited control of the sort. Its rather blunt control of the
-underlying algorithm may not persist into future Perls, but the
-ability to characterize the input or output in implementation
-independent ways quite probably will.
+Historically Perl has varied in whether sorting is stable by default.
+If stability matters, it can be controlled explicitly by using the
+L<sort> pragma.
Examples:
package main;
my @new = sort Other::backwards @old;
- # guarantee stability, regardless of algorithm
+ # guarantee stability
use sort 'stable';
my @new = sort { substr($a, 3, 5) cmp substr($b, 3, 5) } @old;
- # force use of mergesort (not portable outside Perl 5.8)
- use sort '_mergesort'; # note discouraging _
- my @new = sort { substr($a, 3, 5) cmp substr($b, 3, 5) } @old;
-
Warning: syntactical care is required when sorting the list returned from
a function. If you want to sort the list returned by the function call
C<find_records(@key)>, you can use:
bits, or three octal digits: C<0750> (the leading 0 indicates octal
and isn't one of the digits). The L<C<umask>|/umask EXPR> value is such
a number representing disabled permissions bits. The permission (or
-"mode") values you pass L<C<mkdir>|/mkdir FILENAME,MASK> or
+"mode") values you pass L<C<mkdir>|/mkdir FILENAME,MODE> or
L<C<sysopen>|/sysopen FILEHANDLE,FILENAME,MODE> are modified by your
umask, so even if you tell
L<C<sysopen>|/sysopen FILEHANDLE,FILENAME,MODE> to create a file with
Here's some advice: supply a creation mode of C<0666> for regular
files (in L<C<sysopen>|/sysopen FILEHANDLE,FILENAME,MODE>) and one of
-C<0777> for directories (in L<C<mkdir>|/mkdir FILENAME,MASK>) and
+C<0777> for directories (in L<C<mkdir>|/mkdir FILENAME,MODE>) and
executable files. This gives users the freedom of
choice: if they want protected files, they might choose process umasks
of C<022>, C<027>, or even the particularly antisocial mask of C<077>.
use strict qw(subs vars refs);
use subs qw(afunc blurfl);
use warnings qw(all);
- use sort qw(stable _quicksort _mergesort);
+ use sort qw(stable);
Some of these pseudo-modules import semantics into the current
block scope (like L<C<strict>|strict> or L<C<integer>|integer>, unlike
https://perl5.git.perl.org / perl5.git / blobdiff