From: Tom Christiansen <tchrist@mox.perl.com>
Subject: ANNOUNCE: perl5.005_57 released!
Date: 26 May 1999 06:34:08 -0700

On the road to this years major release of perl, the "five six" (5.006)
release, which is itself expected later this summer, several milestone
alpha-like releases must first be crossed.  5.005_57 is the latest of
these.  This is a developer release, so is considered wholly experimental;
the usual caveats about its being for the brave or foolish continue
to apply.  If you install this, make sure to read the INSTALL and README
files first.

But even if you won't care to be on the cutting edge, you might care
to pick this release up for the documentation alone.  I've just spent a
couple weeks extending, correcting, clarifying, and wordsmithing about
80% of the standard docset.  

http://www.perl.com/CPAN-local/src/ contains what you want.

Here are the release notes.

--tom

    NAME
	perldelta - what's new for perl5.006 (as of 5.005_57)

    DESCRIPTION
	This document describes differences between the 5.005 release
	and this one.

    Incompatible Changes
      Perl Source Incompatibilities

	None known at this time.

      C Source Incompatibilities

	`PERL_POLLUTE'
	    Release 5.005 grandfathered old global symbol names by
	    providing preprocessor macros for extension source
	    compatibility. As of release 5.006, these preprocessor
	    definitions are not available by default. You need to
	    explicitly compile perl with `-DPERL_POLLUTE' to get these
	    definitions. For extensions still using the old symbols,
	    this option can be specified via MakeMaker:

		perl Makefile.PL POLLUTE=1

	`PERL_POLLUTE_MALLOC'
	    Enabling Perl's malloc in release 5.005 and earlier caused
	    the namespace of system versions of the malloc family of
	    functions to be usurped by the Perl versions, since by
	    default they used the same names.

	    Besides causing problems on platforms that do not allow
	    these functions to be cleanly replaced, this also meant that
	    the system versions could not be called in programs that
	    used Perl's malloc. Previous versions of Perl have allowed
	    this behaviour to be suppressed with the HIDEMYMALLOC and
	    EMBEDMYMALLOC preprocessor definitions.

	    As of release 5.006, Perl's malloc family of functions have
	    default names distinct from the system versions. You need to
	    explicitly compile perl with `-DPERL_POLLUTE_MALLOC' to get
	    the older behaviour. HIDEMYMALLOC and EMBEDMYMALLOC have no
	    effect, since the behaviour they enabled is now the default.

	    Note that these functions do not constitute Perl's memory
	    allocation API. See the section on "Memory Allocation" in
	    the perlguts manpage for further information about that.

	`PL_na' and `dTHR' Issues
	    The `PL_na' global is now thread local, so a `dTHR'
	    declaration is needed in the scope in which the global
	    appears. XSUBs should handle this automatically, but if you
	    have used `PL_na' in support functions, you either need to
	    change the `PL_na' to a local variable (which is
	    recommended), or put in a `dTHR'.

      Compatible C Source API Changes

	`PATCHLEVEL' is now `PERL_VERSION'
	    The cpp macros `PERL_REVISION', `PERL_VERSION', and
	    `PERL_SUBVERSION' are now available by default from perl.h,
	    and reflect the base revision, patchlevel, and subversion
	    respectively. `PERL_REVISION' had no prior equivalent, while
	    `PERL_VERSION' and `PERL_SUBVERSION' were previously
	    available as `PATCHLEVEL' and `SUBVERSION'.

	    The new names cause less pollution of the cpp namespace and
	    reflect what the numbers have come to stand for in common
	    practice. For compatibility, the old names are still
	    supported when patchlevel.h is explicitly included (as
	    required before), so there is no source incompatibility from
	    the change.

      Binary Incompatibilities

	This release is not binary compatible with the 5.005 release or
	its maintenance versions.

    Core Changes
      Unicode and UTF-8 support

	Perl can optionally use UTF-8 as its internal representation for
	character strings. The `use utf8' pragma enables this support in
	the current lexical scope. See the utf8 manpage for more
	information.

      Lexically scoped warning categories

	You can now control the granularity of warnings emitted by perl
	at a finer level using the `use warning' pragma. See the warning
	manpage for details.

      Binary numbers supported

	Binary numbers are now supported as literals, in s?printf
	formats, and `oct()':

	    $answer = 0b101010;
	    printf "The answer is: %b\n", oct("0b101010");

      syswrite() ease-of-use

	The length argument of `syswrite()' is now optional.

      64-bit support

	Better 64-bit support -- but full support still a distant goal.
	One must Configure with -Duse64bits to get Configure to probe
	for the extent of 64-bit support. Depending on the platform
	(hints file) more or less 64-awareness becomes available. As of
	5.005_54 at least somewhat 64-bit aware platforms are HP-UX 11
	or better, Solaris 2.6 or better, IRIX 6.2 or better. Naturally
	64-bit platforms like Digital Unix and UNICOS also have 64-bit
	support.

      Better syntax checks on parenthesized unary operators

	Expressions such as:

	    print defined(&foo,&bar,&baz);
	    print uc("foo","bar","baz");
	    undef($foo,&bar);

	used to be accidentally allowed in earlier versions, and
	produced unpredictable behaviour. Some produced ancillary
	warnings when used in this way; others silently did the wrong
	thing.

	The parenthesized forms of most unary operators that expect a
	single argument now ensure that they are not called with more
	than one argument, making the cases shown above syntax errors.
	The usual behaviour of:

	    print defined &foo, &bar, &baz;
	    print uc "foo", "bar", "baz";
	    undef $foo, &bar;

	remains unchanged. See the perlop manpage.

      Improved `qw//' operator

	The `qw//' operator is now evaluated at compile time into a true
	list instead of being replaced with a run time call to
	`split()'. This removes the confusing misbehaviour of `qw//' in
	scalar context, which had inherited that behaviour from split().

	Thus:

	    $foo = ($bar) = qw(a b c); print "$foo|$bar\n";

	now correctly prints "3|a", instead of "2|a".

      pack() format 'Z' supported

	The new format type 'Z' is useful for packing and unpacking
	null-terminated strings. See the section on "pack" in the
	perlfunc manpage.

      pack() format modifier '!' supported

	The new format type modifier '!' is useful for packing and
	unpacking native shorts, ints, and longs. See the section on
	"pack" in the perlfunc manpage.

      $^X variables may now have names longer than one character

	Formerly, $^X was synonymous with ${"\cX"}, but $^XY was a
	syntax error. Now variable names that begin with a control
	character may be arbitrarily long. However, for compatibility
	reasons, these variables *must* be written with explicit braces,
	as `${^XY}' for example. `${^XYZ}' is synonymous with
	${"\cXYZ"}. Variable names with more than one control character,
	such as `${^XY^Z}', are illegal.

	The old syntax has not changed. As before, `^X' may be either a
	literal control-X character or the two-character sequence
	`caret' plus `X'. When braces are omitted, the variable name
	stops after the control character. Thus `"$^XYZ"' continues to
	be synonymous with `$^X . "YZ"' as before.

	As before, lexical variables may not have names beginning with
	control characters. As before, variables whose names begin with
	a control character are always forced to be in package `main'.
	All such variables are reserved for future extensions, except
	those that begin with `^_', which may be used by user programs
	and is guaranteed not to acquire special meaning in any future
	version of Perl.

    Significant bug fixes
      <HANDLE> on empty files

	With `$/' set to `undef', slurping an empty file returns a
	string of zero length (instead of `undef', as it used to) the
	first time the HANDLE is read. Further reads yield `undef'.

	This means that the following will append "foo" to an empty file
	(it used to do nothing):

	    perl -0777 -pi -e 's/^/foo/' empty_file

	The behaviour of:

	    perl -pi -e 's/^/foo/' empty_file

	is unchanged (it continues to leave the file empty).

      `eval '...'' improvements

	Line numbers (as reflected by caller() and most diagnostics)
	within `eval '...'' were often incorrect when here documents
	were involved. This has been corrected.

	Lexical lookups for variables appearing in `eval '...'' within
	functions that were themselves called within an `eval '...''
	were searching the wrong place for lexicals. The lexical search
	now correctly ends at the subroutine's block boundary.

	Parsing of here documents used to be flawed when they appeared
	as the replacement expression in `eval 's/.../.../e''. This has
	been fixed.

      Automatic flushing of output buffers

	fork(), exec(), system(), qx//, and pipe open()s now flush
	buffers of all files opened for output when the operation was
	attempted. This mostly eliminates confusing buffering mishaps
	suffered by users unaware of how Perl internally handles I/O.

    Supported Platforms
	*   VM/ESA is now supported.

	*   Siemens BS2000 is now supported under the POSIX Shell.

	*   The Mach CThreads (NEXTSTEP, OPENSTEP) are now supported by the
	    Thread extension.

	*   GNU/Hurd is now supported.

	*   Rhapsody is now supported.

    New tests
	op/io_const
	    IO constants (SEEK_*, _IO*).

	op/io_dir
	    Directory-related IO methods (new, read, close, rewind, tied
	    delete).

	op/io_multihomed
	    INET sockets with multi-homed hosts.

	op/io_poll
	    IO poll().

	op/io_unix
	    UNIX sockets.

	op/filetest
	    File test operators.

	op/lex_assign
	    Verify operations that access pad objects (lexicals and
	    temporaries).

    Modules and Pragmata
      Modules

	Dumpvalue
	    Added Dumpvalue module provides screen dumps of Perl data.

	Benchmark
	    You can now run tests for *n* seconds instead of guessing
	    the right number of tests to run: e.g. timethese(-5, ...)
	    will run each code for at least 5 CPU seconds. Zero as the
	    "number of repetitions" means "for at least 3 CPU seconds".
	    The output format has also changed. For example:

	    use Benchmark;$x=3;timethese(-
	    5,{a=>sub{$x*$x},b=>sub{$x**2}})

	    will now output something like this:

	    Benchmark: running a, b, each for at least 5 CPU seconds...
	    a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @
	    200551.91/s (n=1156516) b: 4 wallclock secs ( 5.00 usr +
	    0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686)

	    New features: "each for at least N CPU seconds...",
	    "wallclock secs", and the "@ operations/CPU second
	    (n=operations)".

	Devel::Peek
	    The Devel::Peek module provides access to the internal
	    representation of Perl variables and data. It is a data
	    debugging tool for the XS programmer.

	Fcntl
	    More Fcntl constants added: F_SETLK64, F_SETLKW64,
	    O_LARGEFILE for large (more than 4G) file access (64-bit
	    support is not yet working, though, so no need to get overly
	    excited), Free/Net/OpenBSD locking behaviour flags F_FLOCK,
	    F_POSIX, Linux F_SHLCK, and O_ACCMODE: the mask of O_RDONLY,
	    O_WRONLY, and O_RDWR.

	File::Spec
	    New methods have been added to the File::Spec module:
	    devnull() returns the name of the null device (/dev/null on
	    Unix) and tmpdir() the name of the temp directory (normally
	    /tmp on Unix). There are now also methods to convert between
	    absolute and relative filenames: abs2rel() and rel2abs().
	    For compatibility with operating systems that specify volume
	    names in file paths, the splitpath(), splitdir(), and
	    catdir() methods have been added.

	File::Spec::Functions
	    The new File::Spec::Functions modules provides a function
	    interface to the File::Spec module. Allows shorthand

		$fullname = catfile($dir1, $dir2, $file);

	    instead of

		$fullname = File::Spec->catfile($dir1, $dir2, $file);

	Math::BigInt
	    The logical operations `<<', `>>', `&', `|', and `~' are now
	    supported on bigints.

	Math::Complex
	    The accessor methods Re, Im, arg, abs, rho, and theta can
	    now also act as mutators (accessor $z->Re(), mutator $z-
	    >Re(3)).

	Math::Trig
	    A little bit of radial trigonometry (cylindrical and
	    spherical), radial coordinate conversions, and the great
	    circle distance were added.

	SDBM_File
	    An EXISTS method has been added to this module (and
	    sdbm_exists() has been added to the underlying sdbm
	    library), so one can now call exists on an SDBM_File tied
	    hash and get the correct result, rather than a runtime
	    error.

	Time::Local
	    The timelocal() and timegm() functions used to silently
	    return bogus results when the date exceeded the machine's
	    integer range. They now consistently croak() if the date
	    falls in an unsupported range.

	Win32
	    The error return value in list context has been changed for
	    all functions that return a list of values. Previously these
	    functions returned a list with a single element `undef' if
	    an error occurred. Now these functions return the empty list
	    in these situations. This applies to the following
	    functions:

		Win32::FsType
		Win32::GetOSVersion

	    The remaining functions are unchanged and continue to return
	    `undef' on error even in list context.

	    The Win32::SetLastError(ERROR) function has been added as a
	    complement to the Win32::GetLastError() function.

	    The new Win32::GetFullPathName(FILENAME) returns the full
	    absolute pathname for FILENAME in scalar context. In list
	    context it returns a two-element list containing the fully
	    qualified directory name and the filename.

	DBM Filters
	    A new feature called "DBM Filters" has been added to all the
	    DBM modules--DB_File, GDBM_File, NDBM_File, ODBM_File, and
	    SDBM_File. DBM Filters add four new methods to each DBM
	    module:

		filter_store_key
		filter_store_value
		filter_fetch_key
		filter_fetch_value

	    These can be used to filter key-value pairs before the pairs
	    are written to the database or just after they are read from
	    the database. See the perldbmfilter manpage for further
	    information.

      Pragmata

	`use utf8' to enable UTF-8 and Unicode support.

	Lexical warnings pragma, `use warning;', to control optional
	warnings.

	`use filetest' to control the behaviour of filetests (`-r' `-w'
	...). Currently only one subpragma implemented, "use filetest
	'access';", that enables the use of access(2) or equivalent to
	check permissions instead of using stat(2) as usual. This
	matters in filesystems where there are ACLs (access control
	lists): the stat(2) might lie, but access(2) knows better.

    Utility Changes
	Todo.

    Documentation Changes
	perlopentut.pod
	    A tutorial on using open() effectively.

	perlreftut.pod
	    A tutorial that introduces the essentials of references.

	perltootc.pod
	    A tutorial on managing class data for object modules.

    New Diagnostics
	/%s/: Unrecognized escape \\%c passed through
	(W) You used a backslash-character combination which is not
	recognized by Perl. This combination appears in an interpolated
	variable or a `''-delimited regular expression.

	Unrecognized escape \\%c passed through
	(W) You used a backslash-character combination which is not
	recognized by Perl.

	Missing command in piped open
	(W) You used the `open(FH, "| command")' or `open(FH, "command
	|")' construction, but the command was missing or blank.

    Obsolete Diagnostics
	Todo.

    Configuration Changes
	You can use "Configure -Uinstallusrbinperl" which causes
	installperl to skip installing perl also as /usr/bin/perl. This
	is useful if you prefer not to modify /usr/bin for some reason
	or another but harmful because many scripts assume to find Perl
	in /usr/bin/perl.

    BUGS
	If you find what you think is a bug, you might check the headers
	of articles recently posted to the comp.lang.perl.misc
	newsgroup. There may also be information at
	http://www.perl.com/perl/, the Perl Home Page.

	If you believe you have an unreported bug, please run the
	perlbug program included with your release. Make sure to trim
	your bug down to a tiny but sufficient test case. Your bug
	report, along with the output of `perl -V', will be sent off to
	perlbug@perl.com to be analysed by the Perl porting team.

    SEE ALSO
	The Changes file for exhaustive details on what changed.

	The INSTALL file for how to build Perl.

	The README file for general stuff.

	The Artistic and Copying files for copyright information.

    HISTORY
	Written by Gurusamy Sarathy <gsar@umich.edu>, with many
	contributions from The Perl Porters.

	Send omissions or corrections to <perlbug@perl.com>.
-- 
    That means I'll have to use $ans to suppress newlines now.  
    Life is ridiculous. 
        --Larry Wall in Configure from the perl distribution