3 perldelta - what's new for perl5.006 (as of 5.005_54)
7 This document describes differences between the 5.005 release and this one.
9 =head1 Incompatible Changes
11 =head2 Perl Source Incompatibilities
13 None known at this time.
15 =head2 C Source Incompatibilities
21 Release 5.005 grandfathered old global symbol names by providing preprocessor
22 macros for extension source compatibility. As of release 5.006, these
23 preprocessor definitions are not available by default. You need to explicitly
24 compile perl with C<-DPERL_POLLUTE> in order to get these definitions.
26 =item C<PERL_POLLUTE_MALLOC>
28 Enabling the use of Perl's malloc in release 5.005 and earlier caused
29 the namespace of system versions of the malloc family of functions to
30 be usurped by the Perl versions of these functions, since they used the
31 same names by default.
33 Besides causing problems on platforms that do not allow these functions to
34 be cleanly replaced, this also meant that the system versions could not
35 be called in programs that used Perl's malloc. Previous versions of Perl
36 have allowed this behavior to be suppressed with the HIDEMYMALLOC and
37 EMBEDMYMALLOC preprocessor definitions.
39 As of release 5.006, Perl's malloc family of functions have default names
40 distinct from the system versions. You need to explicitly compile perl with
41 C<-DPERL_POLLUTE_MALLOC> in order to get the older behavior. HIDEMYMALLOC
42 and EMBEDMYMALLOC have no effect, since the behavior they enabled is now
45 Note that these functions do B<not> constitute Perl's memory allocation API.
46 See L<perlguts/"Memory Allocation"> for further information about that.
48 =item C<PL_na> and C<dTHR> Issues
50 The C<PL_na> global is now thread local, so a C<dTHR> declaration is needed
51 in the scope in which it appears. XSUBs should handle this automatically,
52 but if you have used C<PL_na> in support functions, you either need to
53 change the C<PL_na> to a local variable (which is recommended), or put in
58 =head2 Binary Incompatibilities
60 This release is not binary compatible with the 5.005 release and its
65 =head2 Binary numbers supported
67 Binary numbers are now supported as literals, in s?printf formats, and
71 printf "The answer is: %b\n", oct("0b101010");
73 =head2 syswrite() ease-of-use
75 The length argument of C<syswrite()> is now optional.
79 Better 64-bit support -- but full support still a distant goal. One
80 must Configure with -Duse64bits to get Configure to probe for the
81 extent of 64-bit support. Depending on the platform (hints file) more
82 or less 64-awareness becomes available. As of 5.005_54 at least
83 somewhat 64-bit aware platforms are HP-UX 11 or better, Solaris 2.6 or
84 better, IRIX 6.2 or better. Naturally 64-bit platforms like Digital
85 UNIX and UNICOS also have 64-bit support.
87 =head2 Better syntax checks on parenthesized unary operators
91 print defined(&foo,&bar,&baz);
92 print uc("foo","bar","baz");
95 used to be accidentally allowed in earlier versions, and produced
96 unpredictable behavior. Some of them produced ancillary warnings
97 when used in this way, while others silently did the wrong thing.
99 The parenthesized forms of most unary operators that expect a single
100 argument will now ensure that they are not called with more than one
101 argument, making the above cases syntax errors. Note that the usual
104 print defined &foo, &bar, &baz;
105 print uc "foo", "bar", "baz";
108 remains unchanged. See L<perlop>.
110 =item Improved C<qw//> operator
112 The C<qw//> operator is now evaluated at compile time instead of being
113 replaced with a run time call to C<split()>.
115 =head1 Supported Platforms
121 VM/ESA is now supported.
125 Siemens BS200 is now supported.
129 The Mach CThreads (NeXTstep) are now supported by the Thread extension.
139 IO constants (SEEK_*, _IO*).
143 Directory-related IO methods (new, read, close, rewind, tied delete).
145 =item op/io_multihomed
147 INET sockets with multi-homed hosts.
163 Verify operations that access pad objects (lexicals and temporaries).
167 =head1 Modules and Pragmata
175 Added Dumpvalue module provides screen dumps of Perl data.
179 You can now run tests for I<x> seconds instead of guessing the right
180 number of tests to run.
184 More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for
185 large (more than 4G) file access (the 64-bit support is not yet
186 working, though, so no need to get overly excited), Free/Net/OpenBSD
187 locking behaviour flags F_FLOCK, F_POSIX, Linux F_SHLCK, and
188 O_ACCMODE: the mask of O_RDONLY, O_WRONLY, and O_RDWR.
192 The accessors methods Re, Im, arg, abs, rho, theta, methods can
193 ($z->Re()) now also act as mutators ($z->Re(3)).
197 A little bit of radial trigonometry (cylindrical and spherical) added,
198 for example the great circle distance.
204 Lexical warnings pragma, "use warning;", to control optional warnings.
206 Filetest pragma, to control the behaviour of filetests (C<-r> C<-w> ...).
207 Currently only one subpragma implemented, "use filetest 'access';",
208 that enables the use of access(2) or equivalent to check the
209 permissions instead of using stat(2) as usual. This matters
210 in filesystems where there are ACLs (access control lists), the
211 stat(2) might lie, while access(2) knows better.
213 =head1 Utility Changes
217 =head1 Documentation Changes
221 =item perlopentut.pod
223 A tutorial on using open() effectively.
227 A tutorial that introduces the essentials of references.
231 =head1 New Diagnostics
233 =item /%s/: Unrecognized escape \\%c passed through
235 (W) You used a backslash-character combination which is not recognized
236 by Perl. This combination appears in an interpolated variable or a
237 C<'>-delimited regular expression.
239 =item Unrecognized escape \\%c passed through
241 (W) You used a backslash-character combination which is not recognized
244 =item Missing command in piped open
246 (W) You used the C<open(FH, "| command")> or C<open(FH, "command |")>
247 construction, but the command was missing or blank.
249 =head1 Obsolete Diagnostics
253 =head1 Configuration Changes
255 You can use "Configure -Uinstallusrbinperl" which causes installperl
256 to skip installing perl also as /usr/bin/perl. This is useful if you
257 prefer not to modify /usr/bin for some reason or another but harmful
258 because many scripts assume to find Perl in /usr/bin/perl.
262 If you find what you think is a bug, you might check the headers of
263 recently posted articles in the comp.lang.perl.misc newsgroup.
264 There may also be information at http://www.perl.com/perl/, the Perl
267 If you believe you have an unreported bug, please run the B<perlbug>
268 program included with your release. Make sure you trim your bug down
269 to a tiny but sufficient test case. Your bug report, along with the
270 output of C<perl -V>, will be sent off to <F<perlbug@perl.com>> to be
271 analysed by the Perl porting team.
275 The F<Changes> file for exhaustive details on what changed.
277 The F<INSTALL> file for how to build Perl.
279 The F<README> file for general stuff.
281 The F<Artistic> and F<Copying> files for copyright information.
285 Written by Gurusamy Sarathy <F<gsar@umich.edu>>, with many contributions
286 from The Perl Porters.
288 Send omissions or corrections to <F<perlbug@perl.com>>.