| 1 | =head1 NAME |
| 2 | |
| 3 | perl571delta - what's new for perl v5.7.1 |
| 4 | |
| 5 | =head1 DESCRIPTION |
| 6 | |
| 7 | This document describes differences between the 5.7.0 release and the |
| 8 | 5.7.1 release. |
| 9 | |
| 10 | (To view the differences between the 5.6.0 release and the 5.7.0 |
| 11 | release, see L<perl570delta>.) |
| 12 | |
| 13 | =head1 Security Vulnerability Closed |
| 14 | |
| 15 | (This change was already made in 5.7.0 but bears repeating here.) |
| 16 | |
| 17 | A potential security vulnerability in the optional suidperl component |
| 18 | of Perl was identified in August 2000. suidperl is neither built nor |
| 19 | installed by default. As of April 2001 the only known vulnerable |
| 20 | platform is Linux, most likely all Linux distributions. CERT and |
| 21 | various vendors and distributors have been alerted about the vulnerability. |
| 22 | See http://www.cpan.org/src/5.0/sperl-2000-08-05/sperl-2000-08-05.txt |
| 23 | for more information. |
| 24 | |
| 25 | The problem was caused by Perl trying to report a suspected security |
| 26 | exploit attempt using an external program, /bin/mail. On Linux |
| 27 | platforms the /bin/mail program had an undocumented feature which |
| 28 | when combined with suidperl gave access to a root shell, resulting in |
| 29 | a serious compromise instead of reporting the exploit attempt. If you |
| 30 | don't have /bin/mail, or if you have 'safe setuid scripts', or if |
| 31 | suidperl is not installed, you are safe. |
| 32 | |
| 33 | The exploit attempt reporting feature has been completely removed from |
| 34 | all the Perl 5.7 releases (and will be gone also from the maintenance |
| 35 | release 5.6.1), so that particular vulnerability isn't there anymore. |
| 36 | However, further security vulnerabilities are, unfortunately, always |
| 37 | possible. The suidperl code is being reviewed and if deemed too risky |
| 38 | to continue to be supported, it may be completely removed from future |
| 39 | releases. In any case, suidperl should only be used by security |
| 40 | experts who know exactly what they are doing and why they are using |
| 41 | suidperl instead of some other solution such as sudo |
| 42 | ( see http://www.courtesan.com/sudo/ ). |
| 43 | |
| 44 | =head1 Incompatible Changes |
| 45 | |
| 46 | =over 4 |
| 47 | |
| 48 | =item * |
| 49 | |
| 50 | Although "you shouldn't do that", it was possible to write code that |
| 51 | depends on Perl's hashed key order (Data::Dumper does this). The new |
| 52 | algorithm "One-at-a-Time" produces a different hashed key order. |
| 53 | More details are in L</"Performance Enhancements">. |
| 54 | |
| 55 | =item * |
| 56 | |
| 57 | The list of filenames from glob() (or <...>) is now by default sorted |
| 58 | alphabetically to be csh-compliant. (bsd_glob() does still sort platform |
| 59 | natively, ASCII or EBCDIC, unless GLOB_ALPHASORT is specified.) |
| 60 | |
| 61 | =back |
| 62 | |
| 63 | =head1 Core Enhancements |
| 64 | |
| 65 | =head2 AUTOLOAD Is Now Lvaluable |
| 66 | |
| 67 | AUTOLOAD is now lvaluable, meaning that you can add the :lvalue attribute |
| 68 | to AUTOLOAD subroutines and you can assign to the AUTOLOAD return value. |
| 69 | |
| 70 | =head2 PerlIO is Now The Default |
| 71 | |
| 72 | =over 4 |
| 73 | |
| 74 | =item * |
| 75 | |
| 76 | IO is now by default done via PerlIO rather than system's "stdio". |
| 77 | PerlIO allows "layers" to be "pushed" onto a file handle to alter the |
| 78 | handle's behaviour. Layers can be specified at open time via 3-arg |
| 79 | form of open: |
| 80 | |
| 81 | open($fh,'>:crlf :utf8', $path) || ... |
| 82 | |
| 83 | or on already opened handles via extended C<binmode>: |
| 84 | |
| 85 | binmode($fh,':encoding(iso-8859-7)'); |
| 86 | |
| 87 | The built-in layers are: unix (low level read/write), stdio (as in |
| 88 | previous Perls), perlio (re-implementation of stdio buffering in a |
| 89 | portable manner), crlf (does CRLF <=> "\n" translation as on Win32, |
| 90 | but available on any platform). A mmap layer may be available if |
| 91 | platform supports it (mostly UNIXes). |
| 92 | |
| 93 | Layers to be applied by default may be specified via the 'open' pragma. |
| 94 | |
| 95 | See L</"Installation and Configuration Improvements"> for the effects |
| 96 | of PerlIO on your architecture name. |
| 97 | |
| 98 | =item * |
| 99 | |
| 100 | File handles can be marked as accepting Perl's internal encoding of Unicode |
| 101 | (UTF-8 or UTF-EBCDIC depending on platform) by a pseudo layer ":utf8" : |
| 102 | |
| 103 | open($fh,">:utf8","Uni.txt"); |
| 104 | |
| 105 | Note for EBCDIC users: the pseudo layer ":utf8" is erroneously named |
| 106 | for you since it's not UTF-8 what you will be getting but instead |
| 107 | UTF-EBCDIC. See L<perlunicode>, L<utf8>, and |
| 108 | http://www.unicode.org/unicode/reports/tr16/ for more information. |
| 109 | In future releases this naming may change. |
| 110 | |
| 111 | =item * |
| 112 | |
| 113 | File handles can translate character encodings from/to Perl's internal |
| 114 | Unicode form on read/write via the ":encoding()" layer. |
| 115 | |
| 116 | =item * |
| 117 | |
| 118 | File handles can be opened to "in memory" files held in Perl scalars via: |
| 119 | |
| 120 | open($fh,'>', \$variable) || ... |
| 121 | |
| 122 | =item * |
| 123 | |
| 124 | Anonymous temporary files are available without need to |
| 125 | 'use FileHandle' or other module via |
| 126 | |
| 127 | open($fh,"+>", undef) || ... |
| 128 | |
| 129 | That is a literal undef, not an undefined value. |
| 130 | |
| 131 | =item * |
| 132 | |
| 133 | The list form of C<open> is now implemented for pipes (at least on UNIX): |
| 134 | |
| 135 | open($fh,"-|", 'cat', '/etc/motd') |
| 136 | |
| 137 | creates a pipe, and runs the equivalent of exec('cat', '/etc/motd') in |
| 138 | the child process. |
| 139 | |
| 140 | =item * |
| 141 | |
| 142 | The following builtin functions are now overridable: chop(), chomp(), |
| 143 | each(), keys(), pop(), push(), shift(), splice(), unshift(). |
| 144 | |
| 145 | =item * |
| 146 | |
| 147 | Formats now support zero-padded decimal fields. |
| 148 | |
| 149 | =item * |
| 150 | |
| 151 | Perl now tries internally to use integer values in numeric conversions |
| 152 | and basic arithmetics (+ - * /) if the arguments are integers, and |
| 153 | tries also to keep the results stored internally as integers. |
| 154 | This change leads into often slightly faster and always less lossy |
| 155 | arithmetics. (Previously Perl always preferred floating point numbers |
| 156 | in its math.) |
| 157 | |
| 158 | =item * |
| 159 | |
| 160 | The printf() and sprintf() now support parameter reordering using the |
| 161 | C<%\d+\$> and C<*\d+\$> syntaxes. For example |
| 162 | |
| 163 | print "%2\$s %1\$s\n", "foo", "bar"; |
| 164 | |
| 165 | will print "bar foo\n"; This feature helps in writing |
| 166 | internationalised software. |
| 167 | |
| 168 | =item * |
| 169 | |
| 170 | Unicode in general should be now much more usable. Unicode can be |
| 171 | used in hash keys, Unicode in regular expressions should work now, |
| 172 | Unicode in tr/// should work now (though tr/// seems to be a |
| 173 | particularly tricky to get right, so you have been warned) |
| 174 | |
| 175 | =item * |
| 176 | |
| 177 | The Unicode Character Database coming with Perl has been upgraded |
| 178 | to Unicode 3.1. For more information, see http://www.unicode.org/ , |
| 179 | and http://www.unicode.org/unicode/reports/tr27/ |
| 180 | |
| 181 | For developers interested in enhancing Perl's Unicode capabilities: |
| 182 | almost all the UCD files are included with the Perl distribution in |
| 183 | the lib/unicode subdirectory. The most notable omission, for space |
| 184 | considerations, is the Unihan database. |
| 185 | |
| 186 | =item * |
| 187 | |
| 188 | The Unicode character classes \p{Blank} and \p{SpacePerl} have been |
| 189 | added. "Blank" is like C isblank(), that is, it contains only |
| 190 | "horizontal whitespace" (the space character is, the newline isn't), |
| 191 | and the "SpacePerl" is the Unicode equivalent of C<\s> (\p{Space} |
| 192 | isn't, since that includes the vertical tabulator character, whereas |
| 193 | C<\s> doesn't.) |
| 194 | |
| 195 | =back |
| 196 | |
| 197 | =head2 Signals Are Now Safe |
| 198 | |
| 199 | Perl used to be fragile in that signals arriving at inopportune moments |
| 200 | could corrupt Perl's internal state. |
| 201 | |
| 202 | =head1 Modules and Pragmata |
| 203 | |
| 204 | =head2 New Modules |
| 205 | |
| 206 | =over 4 |
| 207 | |
| 208 | =item * |
| 209 | |
| 210 | B::Concise, by Stephen McCamant, is a new compiler backend for |
| 211 | walking the Perl syntax tree, printing concise info about ops. |
| 212 | The output is highly customisable. |
| 213 | |
| 214 | See L<B::Concise> for more information. |
| 215 | |
| 216 | =item * |
| 217 | |
| 218 | Class::ISA, by Sean Burke, for reporting the search path for a |
| 219 | class's ISA tree, has been added. |
| 220 | |
| 221 | See L<Class::ISA> for more information. |
| 222 | |
| 223 | =item * |
| 224 | |
| 225 | Cwd has now a split personality: if possible, an extension is used, |
| 226 | (this will hopefully be both faster and more secure and robust) but |
| 227 | if not possible, the familiar Perl library implementation is used. |
| 228 | |
| 229 | =item * |
| 230 | |
| 231 | Digest, a frontend module for calculating digests (checksums), |
| 232 | from Gisle Aas, has been added. |
| 233 | |
| 234 | See L<Digest> for more information. |
| 235 | |
| 236 | =item * |
| 237 | |
| 238 | Digest::MD5 for calculating MD5 digests (checksums), by Gisle Aas, |
| 239 | has been added. |
| 240 | |
| 241 | use Digest::MD5 'md5_hex'; |
| 242 | |
| 243 | $digest = md5_hex("Thirsty Camel"); |
| 244 | |
| 245 | print $digest, "\n"; # 01d19d9d2045e005c3f1b80e8b164de1 |
| 246 | |
| 247 | NOTE: the MD5 backward compatibility module is deliberately not |
| 248 | included since its use is discouraged. |
| 249 | |
| 250 | See L<Digest::MD5> for more information. |
| 251 | |
| 252 | =item * |
| 253 | |
| 254 | Encode, by Nick Ing-Simmons, provides a mechanism to translate |
| 255 | between different character encodings. Support for Unicode, |
| 256 | ISO-8859-*, ASCII, CP*, KOI8-R, and three variants of EBCDIC are |
| 257 | compiled in to the module. Several other encodings (like Japanese, |
| 258 | Chinese, and MacIntosh encodings) are included and will be loaded at |
| 259 | runtime. |
| 260 | |
| 261 | Any encoding supported by Encode module is also available to the |
| 262 | ":encoding()" layer if PerlIO is used. |
| 263 | |
| 264 | See L<Encode> for more information. |
| 265 | |
| 266 | =item * |
| 267 | |
| 268 | Filter::Simple is an easy-to-use frontend to Filter::Util::Call, |
| 269 | from Damian Conway. |
| 270 | |
| 271 | # in MyFilter.pm: |
| 272 | |
| 273 | package MyFilter; |
| 274 | |
| 275 | use Filter::Simple sub { |
| 276 | while (my ($from, $to) = splice @_, 0, 2) { |
| 277 | s/$from/$to/g; |
| 278 | } |
| 279 | }; |
| 280 | |
| 281 | 1; |
| 282 | |
| 283 | # in user's code: |
| 284 | |
| 285 | use MyFilter qr/red/ => 'green'; |
| 286 | |
| 287 | print "red\n"; # this code is filtered, will print "green\n" |
| 288 | print "bored\n"; # this code is filtered, will print "bogreen\n" |
| 289 | |
| 290 | no MyFilter; |
| 291 | |
| 292 | print "red\n"; # this code is not filtered, will print "red\n" |
| 293 | |
| 294 | See L<Filter::Simple> for more information. |
| 295 | |
| 296 | =item * |
| 297 | |
| 298 | Filter::Util::Call, by Paul Marquess, provides you with the |
| 299 | framework to write I<Source Filters> in Perl. For most uses |
| 300 | the frontend Filter::Simple is to be preferred. |
| 301 | See L<Filter::Util::Call> for more information. |
| 302 | |
| 303 | =item * |
| 304 | |
| 305 | Locale::Constants, Locale::Country, Locale::Currency, and Locale::Language, |
| 306 | from Neil Bowers, have been added. They provide the codes for various |
| 307 | locale standards, such as "fr" for France, "usd" for US Dollar, and |
| 308 | "jp" for Japanese. |
| 309 | |
| 310 | use Locale::Country; |
| 311 | |
| 312 | $country = code2country('jp'); # $country gets 'Japan' |
| 313 | $code = country2code('Norway'); # $code gets 'no' |
| 314 | |
| 315 | See L<Locale::Constants>, L<Locale::Country>, L<Locale::Currency>, |
| 316 | and L<Locale::Language> for more information. |
| 317 | |
| 318 | =item * |
| 319 | |
| 320 | MIME::Base64, by Gisle Aas, allows you to encode data in base64. |
| 321 | |
| 322 | use MIME::Base64; |
| 323 | |
| 324 | $encoded = encode_base64('Aladdin:open sesame'); |
| 325 | $decoded = decode_base64($encoded); |
| 326 | |
| 327 | print $encoded, "\n"; # "QWxhZGRpbjpvcGVuIHNlc2FtZQ==" |
| 328 | |
| 329 | See L<MIME::Base64> for more information. |
| 330 | |
| 331 | =item * |
| 332 | |
| 333 | MIME::QuotedPrint, by Gisle Aas, allows you to encode data in |
| 334 | quoted-printable encoding. |
| 335 | |
| 336 | use MIME::QuotedPrint; |
| 337 | |
| 338 | $encoded = encode_qp("Smiley in Unicode: \x{263a}"); |
| 339 | $decoded = decode_qp($encoded); |
| 340 | |
| 341 | print $encoded, "\n"; # "Smiley in Unicode: =263A" |
| 342 | |
| 343 | MIME::QuotedPrint has been enhanced to provide the basic methods |
| 344 | necessary to use it with PerlIO::Via as in : |
| 345 | |
| 346 | use MIME::QuotedPrint; |
| 347 | open($fh,">Via(MIME::QuotedPrint)",$path) |
| 348 | |
| 349 | See L<MIME::QuotedPrint> for more information. |
| 350 | |
| 351 | =item * |
| 352 | |
| 353 | PerlIO::Scalar, by Nick Ing-Simmons, provides the implementation of |
| 354 | IO to "in memory" Perl scalars as discussed above. It also serves as |
| 355 | an example of a loadable layer. Other future possibilities include |
| 356 | PerlIO::Array and PerlIO::Code. See L<PerlIO::Scalar> for more |
| 357 | information. |
| 358 | |
| 359 | =item * |
| 360 | |
| 361 | PerlIO::Via, by Nick Ing-Simmons, acts as a PerlIO layer and wraps |
| 362 | PerlIO layer functionality provided by a class (typically implemented |
| 363 | in perl code). |
| 364 | |
| 365 | use MIME::QuotedPrint; |
| 366 | open($fh,">Via(MIME::QuotedPrint)",$path) |
| 367 | |
| 368 | This will automatically convert everything output to C<$fh> |
| 369 | to Quoted-Printable. See L<PerlIO::Via> for more information. |
| 370 | |
| 371 | =item * |
| 372 | |
| 373 | Pod::Text::Overstrike, by Joe Smith, has been added. |
| 374 | It converts POD data to formatted overstrike text. |
| 375 | See L<Pod::Text::Overstrike> for more information. |
| 376 | |
| 377 | =item * |
| 378 | |
| 379 | Switch from Damian Conway has been added. Just by saying |
| 380 | |
| 381 | use Switch; |
| 382 | |
| 383 | you have C<switch> and C<case> available in Perl. |
| 384 | |
| 385 | use Switch; |
| 386 | |
| 387 | switch ($val) { |
| 388 | |
| 389 | case 1 { print "number 1" } |
| 390 | case "a" { print "string a" } |
| 391 | case [1..10,42] { print "number in list" } |
| 392 | case (@array) { print "number in list" } |
| 393 | case /\w+/ { print "pattern" } |
| 394 | case qr/\w+/ { print "pattern" } |
| 395 | case (%hash) { print "entry in hash" } |
| 396 | case (\%hash) { print "entry in hash" } |
| 397 | case (\&sub) { print "arg to subroutine" } |
| 398 | else { print "previous case not true" } |
| 399 | } |
| 400 | |
| 401 | See L<Switch> for more information. |
| 402 | |
| 403 | =item * |
| 404 | |
| 405 | Text::Balanced from Damian Conway has been added, for |
| 406 | extracting delimited text sequences from strings. |
| 407 | |
| 408 | use Text::Balanced 'extract_delimited'; |
| 409 | |
| 410 | ($a, $b) = extract_delimited("'never say never', he never said", "'", ''); |
| 411 | |
| 412 | $a will be "'never say never'", $b will be ', he never said'. |
| 413 | |
| 414 | In addition to extract_delimited() there are also extract_bracketed(), |
| 415 | extract_quotelike(), extract_codeblock(), extract_variable(), |
| 416 | extract_tagged(), extract_multiple(), gen_delimited_pat(), and |
| 417 | gen_extract_tagged(). With these you can implement rather advanced |
| 418 | parsing algorithms. See L<Text::Balanced> for more information. |
| 419 | |
| 420 | =item * |
| 421 | |
| 422 | Tie::RefHash::Nestable, by Edward Avis, allows storing hash references |
| 423 | (unlike the standard Tie::RefHash) The module is contained within |
| 424 | Tie::RefHash. |
| 425 | |
| 426 | =item * |
| 427 | |
| 428 | XS::Typemap, by Tim Jenness, is a test extension that exercises XS |
| 429 | typemaps. Nothing gets installed but for extension writers the code |
| 430 | is worth studying. |
| 431 | |
| 432 | =back |
| 433 | |
| 434 | =head2 Updated And Improved Modules and Pragmata |
| 435 | |
| 436 | =over 4 |
| 437 | |
| 438 | =item * |
| 439 | |
| 440 | B::Deparse should be now more robust. It still far from providing a full |
| 441 | round trip for any random piece of Perl code, though, and is under active |
| 442 | development: expect more robustness in 5.7.2. |
| 443 | |
| 444 | =item * |
| 445 | |
| 446 | Class::Struct can now define the classes in compile time. |
| 447 | |
| 448 | =item * |
| 449 | |
| 450 | Math::BigFloat has undergone much fixing, and in addition the fmod() |
| 451 | function now supports modulus operations. |
| 452 | |
| 453 | ( The fixed Math::BigFloat module is also available in CPAN for those |
| 454 | who can't upgrade their Perl: http://www.cpan.org/authors/id/J/JP/JPEACOCK/ ) |
| 455 | |
| 456 | =item * |
| 457 | |
| 458 | Devel::Peek now has an interface for the Perl memory statistics |
| 459 | (this works only if you are using perl's malloc, and if you have |
| 460 | compiled with debugging). |
| 461 | |
| 462 | =item * |
| 463 | |
| 464 | IO::Socket has now atmark() method, which returns true if the socket |
| 465 | is positioned at the out-of-band mark. The method is also exportable |
| 466 | as a sockatmark() function. |
| 467 | |
| 468 | =item * |
| 469 | |
| 470 | IO::Socket::INET has support for ReusePort option (if your platform |
| 471 | supports it). The Reuse option now has an alias, ReuseAddr. For clarity |
| 472 | you may want to prefer ReuseAddr. |
| 473 | |
| 474 | =item * |
| 475 | |
| 476 | Net::Ping has been enhanced. There is now "external" protocol which |
| 477 | uses Net::Ping::External module which runs external ping(1) and parses |
| 478 | the output. An alpha version of Net::Ping::External is available in |
| 479 | CPAN and in 5.7.2 the Net::Ping::External may be integrated to Perl. |
| 480 | |
| 481 | =item * |
| 482 | |
| 483 | The C<open> pragma allows layers other than ":raw" and ":crlf" when |
| 484 | using PerlIO. |
| 485 | |
| 486 | =item * |
| 487 | |
| 488 | POSIX::sigaction() is now much more flexible and robust. |
| 489 | You can now install coderef handlers, 'DEFAULT', and 'IGNORE' |
| 490 | handlers, installing new handlers was not atomic. |
| 491 | |
| 492 | =item * |
| 493 | |
| 494 | The Test module has been significantly enhanced. Its use is |
| 495 | greatly recommended for module writers. |
| 496 | |
| 497 | =item * |
| 498 | |
| 499 | The utf8:: name space (as in the pragma) provides various |
| 500 | Perl-callable functions to provide low level access to Perl's |
| 501 | internal Unicode representation. At the moment only length() |
| 502 | has been implemented. |
| 503 | |
| 504 | =back |
| 505 | |
| 506 | The following modules have been upgraded from the versions at CPAN: |
| 507 | CPAN, CGI, DB_File, File::Temp, Getopt::Long, Pod::Man, Pod::Text, |
| 508 | Storable, Text-Tabs+Wrap. |
| 509 | |
| 510 | =head1 Performance Enhancements |
| 511 | |
| 512 | =over 4 |
| 513 | |
| 514 | =item * |
| 515 | |
| 516 | Hashes now use Bob Jenkins "One-at-a-Time" hashing key algorithm |
| 517 | ( http://burtleburtle.net/bob/hash/doobs.html ). This algorithm is |
| 518 | reasonably fast while producing a much better spread of values than |
| 519 | the old hashing algorithm (originally by Chris Torek, later tweaked by |
| 520 | Ilya Zakharevich). Hash values output from the algorithm on a hash of |
| 521 | all 3-char printable ASCII keys comes much closer to passing the |
| 522 | DIEHARD random number generation tests. According to perlbench, this |
| 523 | change has not affected the overall speed of Perl. |
| 524 | |
| 525 | =item * |
| 526 | |
| 527 | unshift() should now be noticeably faster. |
| 528 | |
| 529 | =back |
| 530 | |
| 531 | =head1 Utility Changes |
| 532 | |
| 533 | =over 4 |
| 534 | |
| 535 | =item * |
| 536 | |
| 537 | h2xs now produces template README. |
| 538 | |
| 539 | =item * |
| 540 | |
| 541 | s2p has been completely rewritten in Perl. (It is in fact a full |
| 542 | implementation of sed in Perl.) |
| 543 | |
| 544 | =item * |
| 545 | |
| 546 | xsubpp now supports OUT keyword. |
| 547 | |
| 548 | =back |
| 549 | |
| 550 | =head1 New Documentation |
| 551 | |
| 552 | =head2 perlclib |
| 553 | |
| 554 | Internal replacements for standard C library functions. |
| 555 | (Interesting only for extension writers and Perl core hackers.) |
| 556 | |
| 557 | =head2 perliol |
| 558 | |
| 559 | Internals of PerlIO with layers. |
| 560 | |
| 561 | =head2 README.aix |
| 562 | |
| 563 | Documentation on compiling Perl on AIX has been added. AIX has |
| 564 | several different C compilers and getting the right patch level |
| 565 | is essential. On install README.aix will be installed as L<perlaix>. |
| 566 | |
| 567 | =head2 README.bs2000 |
| 568 | |
| 569 | Documentation on compiling Perl on the POSIX-BC platform (an EBCDIC |
| 570 | mainframe environment) has been added. |
| 571 | |
| 572 | This was formerly known as README.posix-bc but the name was considered |
| 573 | to be too confusing (it has nothing to do with the POSIX module or the |
| 574 | POSIX standard). On install README.bs2000 will be installed as L<perlbs2000>. |
| 575 | |
| 576 | =head2 README.macos |
| 577 | |
| 578 | In perl 5.7.1 (and in the 5.6.1) the MacPerl sources have been |
| 579 | synchronised with the standard Perl sources. To compile MacPerl |
| 580 | some additional steps are required, and this file documents those |
| 581 | steps. On install README.macos will be installed as L<perlmacos>. |
| 582 | |
| 583 | =head2 README.mpeix |
| 584 | |
| 585 | The README.mpeix has been podified, which means that this information |
| 586 | about compiling and using Perl on the MPE/iX miniframe platform will |
| 587 | be installed as L<perlmpeix>. |
| 588 | |
| 589 | =head2 README.solaris |
| 590 | |
| 591 | README.solaris has been created and Solaris wisdom from elsewhere |
| 592 | in the Perl documentation has been collected there. On install |
| 593 | README.solaris will be installed as L<perlsolaris>. |
| 594 | |
| 595 | =head2 README.vos |
| 596 | |
| 597 | The README.vos has been podified, which means that this information |
| 598 | about compiling and using Perl on the Stratus VOS miniframe platform |
| 599 | will be installed as L<perlvos>. |
| 600 | |
| 601 | =head2 Porting/repository.pod |
| 602 | |
| 603 | Documentation on how to use the Perl source repository has been added. |
| 604 | |
| 605 | =head1 Installation and Configuration Improvements |
| 606 | |
| 607 | =over 4 |
| 608 | |
| 609 | =item * |
| 610 | |
| 611 | Because PerlIO is now the default on most platforms, "-perlio" doesn't |
| 612 | get appended to the $Config{archname} (also known as $^O) anymore. |
| 613 | Instead, if you explicitly choose not to use perlio (Configure command |
| 614 | line option -Uuseperlio), you will get "-stdio" appended. |
| 615 | |
| 616 | =item * |
| 617 | |
| 618 | Another change related to the architecture name is that "-64all" |
| 619 | (-Duse64bitall, or "maximally 64-bit") is appended only if your |
| 620 | pointers are 64 bits wide. (To be exact, the use64bitall is ignored.) |
| 621 | |
| 622 | =item * |
| 623 | |
| 624 | APPLLIB_EXP, a less-know configuration-time definition, has been |
| 625 | documented. It can be used to prepend site-specific directories |
| 626 | to Perl's default search path (@INC), see INSTALL for information. |
| 627 | |
| 628 | =item * |
| 629 | |
| 630 | Building Berkeley DB3 for compatibility modes for DB, NDBM, and ODBM |
| 631 | has been documented in INSTALL. |
| 632 | |
| 633 | =item * |
| 634 | |
| 635 | If you are on IRIX or Tru64 platforms, new profiling/debugging options |
| 636 | have been added, see L<perlhack> for more information about pixie and |
| 637 | Third Degree. |
| 638 | |
| 639 | =back |
| 640 | |
| 641 | =head2 New Or Improved Platforms |
| 642 | |
| 643 | For the list of platforms known to support Perl, |
| 644 | see L<perlport/"Supported Platforms">. |
| 645 | |
| 646 | =over 4 |
| 647 | |
| 648 | =item * |
| 649 | |
| 650 | AIX dynamic loading should be now better supported. |
| 651 | |
| 652 | =item * |
| 653 | |
| 654 | After a long pause, AmigaOS has been verified to be happy with Perl. |
| 655 | |
| 656 | =item * |
| 657 | |
| 658 | EBCDIC platforms (z/OS, also known as OS/390, POSIX-BC, and VM/ESA) |
| 659 | have been regained. Many test suite tests still fail and the |
| 660 | co-existence of Unicode and EBCDIC isn't quite settled, but the |
| 661 | situation is much better than with Perl 5.6. See L<perlos390>, |
| 662 | L<perlbs2000> (for POSIX-BC), and L<perlvmesa> for more information. |
| 663 | |
| 664 | =item * |
| 665 | |
| 666 | Building perl with -Duseithreads or -Duse5005threads now works under |
| 667 | HP-UX 10.20 (previously it only worked under 10.30 or later). You will |
| 668 | need a thread library package installed. See README.hpux. |
| 669 | |
| 670 | =item * |
| 671 | |
| 672 | Mac OS Classic (MacPerl has of course been available since |
| 673 | perl 5.004 but now the source code bases of standard Perl |
| 674 | and MacPerl have been synchronised) |
| 675 | |
| 676 | =item * |
| 677 | |
| 678 | NCR MP-RAS is now supported. |
| 679 | |
| 680 | =item * |
| 681 | |
| 682 | NonStop-UX is now supported. |
| 683 | |
| 684 | =item * |
| 685 | |
| 686 | Amdahl UTS is now supported. |
| 687 | |
| 688 | =item * |
| 689 | |
| 690 | z/OS (formerly known as OS/390, formerly known as MVS OE) has now |
| 691 | support for dynamic loading. This is not selected by default, |
| 692 | however, you must specify -Dusedl in the arguments of Configure. |
| 693 | |
| 694 | =back |
| 695 | |
| 696 | =head2 Generic Improvements |
| 697 | |
| 698 | =over 4 |
| 699 | |
| 700 | =item * |
| 701 | |
| 702 | Configure no longer includes the DBM libraries (dbm, gdbm, db, ndbm) |
| 703 | when building the Perl binary. The only exception to this is SunOS 4.x, |
| 704 | which needs them. |
| 705 | |
| 706 | =item * |
| 707 | |
| 708 | Some new Configure symbols, useful for extension writers: |
| 709 | |
| 710 | =over 8 |
| 711 | |
| 712 | =item d_cmsghdr |
| 713 | |
| 714 | For struct cmsghdr. |
| 715 | |
| 716 | =item d_fcntl_can_lock |
| 717 | |
| 718 | Whether fcntl() can be used for file locking. |
| 719 | |
| 720 | =item d_fsync |
| 721 | |
| 722 | =item d_getitimer |
| 723 | |
| 724 | =item d_getpagsz |
| 725 | |
| 726 | For getpagesize(), though you should prefer POSIX::sysconf(_SC_PAGE_SIZE)) |
| 727 | |
| 728 | =item d_msghdr_s |
| 729 | |
| 730 | For struct msghdr. |
| 731 | |
| 732 | =item need_va_copy |
| 733 | |
| 734 | Whether one needs to use Perl_va_copy() to copy varargs. |
| 735 | |
| 736 | =item d_readv |
| 737 | |
| 738 | =item d_recvmsg |
| 739 | |
| 740 | =item d_sendmsg |
| 741 | |
| 742 | =item sig_size |
| 743 | |
| 744 | The number of elements in an array needed to hold all the available signals. |
| 745 | |
| 746 | =item d_sockatmark |
| 747 | |
| 748 | =item d_strtoq |
| 749 | |
| 750 | =item d_u32align |
| 751 | |
| 752 | Whether one needs to access character data aligned by U32 sized pointers. |
| 753 | |
| 754 | =item d_ualarm |
| 755 | |
| 756 | =item d_usleep |
| 757 | |
| 758 | =back |
| 759 | |
| 760 | =item * |
| 761 | |
| 762 | Removed Configure symbols: the PDP-11 memory model settings: huge, |
| 763 | large, medium, models. |
| 764 | |
| 765 | =item * |
| 766 | |
| 767 | SOCKS support is now much more robust. |
| 768 | |
| 769 | =item * |
| 770 | |
| 771 | If your file system supports symbolic links you can build Perl outside |
| 772 | of the source directory by |
| 773 | |
| 774 | mkdir perl/build/directory |
| 775 | cd perl/build/directory |
| 776 | sh /path/to/perl/source/Configure -Dmksymlinks ... |
| 777 | |
| 778 | This will create in perl/build/directory a tree of symbolic links |
| 779 | pointing to files in /path/to/perl/source. The original files are left |
| 780 | unaffected. After Configure has finished you can just say |
| 781 | |
| 782 | make all test |
| 783 | |
| 784 | and Perl will be built and tested, all in perl/build/directory. |
| 785 | |
| 786 | =back |
| 787 | |
| 788 | =head1 Selected Bug Fixes |
| 789 | |
| 790 | Numerous memory leaks and uninitialized memory accesses have been hunted down. |
| 791 | Most importantly anonymous subs used to leak quite a bit. |
| 792 | |
| 793 | =over 4 |
| 794 | |
| 795 | =item * |
| 796 | |
| 797 | chop(@list) in list context returned the characters chopped in |
| 798 | reverse order. This has been reversed to be in the right order. |
| 799 | |
| 800 | =item * |
| 801 | |
| 802 | The order of DESTROYs has been made more predictable. |
| 803 | |
| 804 | =item * |
| 805 | |
| 806 | mkdir() now ignores trailing slashes in the directory name, |
| 807 | as mandated by POSIX. |
| 808 | |
| 809 | =item * |
| 810 | |
| 811 | Attributes (like :shared) didn't work with our(). |
| 812 | |
| 813 | =item * |
| 814 | |
| 815 | The PERL5OPT environment variable (for passing command line arguments |
| 816 | to Perl) didn't work for more than a single group of options. |
| 817 | |
| 818 | =item * |
| 819 | |
| 820 | The tainting behaviour of sprintf() has been rationalized. It does |
| 821 | not taint the result of floating point formats anymore, making the |
| 822 | behaviour consistent with that of string interpolation. |
| 823 | |
| 824 | =item * |
| 825 | |
| 826 | All but the first argument of the IO syswrite() method are now optional. |
| 827 | |
| 828 | =item * |
| 829 | |
| 830 | Tie::ARRAY SPLICE method was broken. |
| 831 | |
| 832 | =item * |
| 833 | |
| 834 | vec() now tries to work with characters <= 255 when possible, but it leaves |
| 835 | higher character values in place. In that case, if vec() was used to modify |
| 836 | the string, it is no longer considered to be utf8-encoded. |
| 837 | |
| 838 | =back |
| 839 | |
| 840 | =head2 Platform Specific Changes and Fixes |
| 841 | |
| 842 | =over 4 |
| 843 | |
| 844 | =item * |
| 845 | |
| 846 | Linux previously had problems related to sockaddrlen when using |
| 847 | accept(), revcfrom() (in Perl: recv()), getpeername(), and getsockname(). |
| 848 | |
| 849 | =item * |
| 850 | |
| 851 | Previously DYNIX/ptx had problems in its Configure probe for non-blocking I/O. |
| 852 | |
| 853 | =item * |
| 854 | |
| 855 | Windows |
| 856 | |
| 857 | =over 8 |
| 858 | |
| 859 | =item * |
| 860 | |
| 861 | Borland C++ v5.5 is now a supported compiler that can build Perl. |
| 862 | However, the generated binaries continue to be incompatible with those |
| 863 | generated by the other supported compilers (GCC and Visual C++). |
| 864 | |
| 865 | =item * |
| 866 | |
| 867 | Win32::GetCwd() correctly returns C:\ instead of C: when at the drive root. |
| 868 | Other bugs in chdir() and Cwd::cwd() have also been fixed. |
| 869 | |
| 870 | =item * |
| 871 | |
| 872 | Duping socket handles with open(F, ">&MYSOCK") now works under Windows 9x. |
| 873 | |
| 874 | =item * |
| 875 | |
| 876 | HTML files will be installed in c:\perl\html instead of c:\perl\lib\pod\html |
| 877 | |
| 878 | =item * |
| 879 | |
| 880 | The makefiles now provide a single switch to bulk-enable all the features |
| 881 | enabled in ActiveState ActivePerl (a popular binary distribution). |
| 882 | |
| 883 | =back |
| 884 | |
| 885 | =back |
| 886 | |
| 887 | =head1 New or Changed Diagnostics |
| 888 | |
| 889 | Two new debugging options have been added: if you have compiled your |
| 890 | Perl with debugging, you can use the -DT and -DR options to trace |
| 891 | tokenising and to add reference counts to displaying variables, |
| 892 | respectively. |
| 893 | |
| 894 | =over 4 |
| 895 | |
| 896 | =item * |
| 897 | |
| 898 | If an attempt to use a (non-blessed) reference as an array index |
| 899 | is made, a warning is given. |
| 900 | |
| 901 | =item * |
| 902 | |
| 903 | C<push @a;> and C<unshift @a;> (with no values to push or unshift) |
| 904 | now give a warning. This may be a problem for generated and eval'ed |
| 905 | code. |
| 906 | |
| 907 | =back |
| 908 | |
| 909 | =head1 Changed Internals |
| 910 | |
| 911 | =over 4 |
| 912 | |
| 913 | =item * |
| 914 | |
| 915 | Some new APIs: ptr_table_clear(), ptr_table_free(), sv_setref_uv(). |
| 916 | For the full list of the available APIs see L<perlapi>. |
| 917 | |
| 918 | =item * |
| 919 | |
| 920 | dTHR and djSP have been obsoleted; the former removed (because it's |
| 921 | a no-op) and the latter replaced with dSP. |
| 922 | |
| 923 | =item * |
| 924 | |
| 925 | Perl now uses system malloc instead of Perl malloc on all 64-bit |
| 926 | platforms, and even in some not-always-64-bit platforms like AIX, |
| 927 | IRIX, and Solaris. This change breaks backward compatibility but |
| 928 | Perl's malloc has problems with large address spaces and also the |
| 929 | speed of vendors' malloc is generally better in large address space |
| 930 | machines (Perl's malloc is mostly tuned for space). |
| 931 | |
| 932 | =back |
| 933 | |
| 934 | =head1 New Tests |
| 935 | |
| 936 | Many new tests have been added. The most notable is probably the |
| 937 | lib/1_compile: it is very notable because running it takes quite a |
| 938 | long time -- it test compiles all the Perl modules in the distribution. |
| 939 | Please be patient. |
| 940 | |
| 941 | =head1 Known Problems |
| 942 | |
| 943 | Note that unlike other sections in this document (which describe |
| 944 | changes since 5.7.0) this section is cumulative containing known |
| 945 | problems for all the 5.7 releases. |
| 946 | |
| 947 | =head2 AIX vac 5.0.0.0 May Produce Buggy Code For Perl |
| 948 | |
| 949 | The AIX C compiler vac version 5.0.0.0 may produce buggy code, |
| 950 | resulting in few random tests failing, but when the failing tests |
| 951 | are run by hand, they succeed. We suggest upgrading to at least |
| 952 | vac version 5.0.1.0, that has been known to compile Perl correctly. |
| 953 | "lslpp -L|grep vac.C" will tell you the vac version. |
| 954 | |
| 955 | =head2 lib/ftmp-security tests warn 'system possibly insecure' |
| 956 | |
| 957 | Don't panic. Read INSTALL 'make test' section instead. |
| 958 | |
| 959 | =head2 lib/io_multihomed Fails In LP64-Configured HP-UX |
| 960 | |
| 961 | The lib/io_multihomed test may hang in HP-UX if Perl has been |
| 962 | configured to be 64-bit. Because other 64-bit platforms do not hang in |
| 963 | this test, HP-UX is suspect. All other tests pass in 64-bit HP-UX. The |
| 964 | test attempts to create and connect to "multihomed" sockets (sockets |
| 965 | which have multiple IP addresses). |
| 966 | |
| 967 | =head2 Test lib/posix Subtest 9 Fails In LP64-Configured HP-UX |
| 968 | |
| 969 | If perl is configured with -Duse64bitall, the successful result of the |
| 970 | subtest 10 of lib/posix may arrive before the successful result of the |
| 971 | subtest 9, which confuses the test harness so much that it thinks the |
| 972 | subtest 9 failed. |
| 973 | |
| 974 | =head2 lib/b test 19 |
| 975 | |
| 976 | The test fails on various platforms (PA64 and IA64 are known), but the |
| 977 | exact cause is still being investigated. |
| 978 | |
| 979 | =head2 Linux With Sfio Fails op/misc Test 48 |
| 980 | |
| 981 | No known fix. |
| 982 | |
| 983 | =head2 sigaction test 13 in VMS |
| 984 | |
| 985 | The test is known to fail; whether it's because of VMS of because |
| 986 | of faulty test is not known. |
| 987 | |
| 988 | =head2 sprintf tests 129 and 130 |
| 989 | |
| 990 | The op/sprintf tests 129 and 130 are known to fail on some platforms. |
| 991 | Examples include any platform using sfio, and Compaq/Tandem's NonStop-UX. |
| 992 | The failing platforms do not comply with the ANSI C Standard, line |
| 993 | 19ff on page 134 of ANSI X3.159 1989 to be exact. (They produce |
| 994 | something else than "1" and "-1" when formatting 0.6 and -0.6 using |
| 995 | the printf format "%.0f", most often they produce "0" and "-0".) |
| 996 | |
| 997 | =head2 Failure of Thread tests |
| 998 | |
| 999 | The subtests 19 and 20 of lib/thr5005.t test are known to fail due to |
| 1000 | fundamental problems in the 5.005 threading implementation. These are |
| 1001 | not new failures--Perl 5.005_0x has the same bugs, but didn't have |
| 1002 | these tests. (Note that support for 5.005-style threading remains |
| 1003 | experimental.) |
| 1004 | |
| 1005 | =head2 Localising a Tied Variable Leaks Memory |
| 1006 | |
| 1007 | use Tie::Hash; |
| 1008 | tie my %tie_hash => 'Tie::StdHash'; |
| 1009 | |
| 1010 | ... |
| 1011 | |
| 1012 | local($tie_hash{Foo}) = 1; # leaks |
| 1013 | |
| 1014 | Code like the above is known to leak memory every time the local() |
| 1015 | is executed. |
| 1016 | |
| 1017 | =head2 Self-tying of Arrays and Hashes Is Forbidden |
| 1018 | |
| 1019 | Self-tying of arrays and hashes is broken in rather deep and |
| 1020 | hard-to-fix ways. As a stop-gap measure to avoid people from getting |
| 1021 | frustrated at the mysterious results (core dumps, most often) it is |
| 1022 | for now forbidden (you will get a fatal error even from an attempt). |
| 1023 | |
| 1024 | =head2 Building Extensions Can Fail Because Of Largefiles |
| 1025 | |
| 1026 | Some extensions like mod_perl are known to have issues with |
| 1027 | `largefiles', a change brought by Perl 5.6.0 in which file offsets |
| 1028 | default to 64 bits wide, where supported. Modules may fail to compile |
| 1029 | at all or compile and work incorrectly. Currently there is no good |
| 1030 | solution for the problem, but Configure now provides appropriate |
| 1031 | non-largefile ccflags, ldflags, libswanted, and libs in the %Config |
| 1032 | hash (e.g., $Config{ccflags_nolargefiles}) so the extensions that are |
| 1033 | having problems can try configuring themselves without the |
| 1034 | largefileness. This is admittedly not a clean solution, and the |
| 1035 | solution may not even work at all. One potential failure is whether |
| 1036 | one can (or, if one can, whether it's a good idea) link together at |
| 1037 | all binaries with different ideas about file offsets, all this is |
| 1038 | platform-dependent. |
| 1039 | |
| 1040 | =head2 The Compiler Suite Is Still Experimental |
| 1041 | |
| 1042 | The compiler suite is slowly getting better but is nowhere near |
| 1043 | working order yet. |
| 1044 | |
| 1045 | =head1 Reporting Bugs |
| 1046 | |
| 1047 | If you find what you think is a bug, you might check the articles |
| 1048 | recently posted to the comp.lang.perl.misc newsgroup and the perl |
| 1049 | bug database at http://bugs.perl.org/ There may also be |
| 1050 | information at http://www.perl.com/perl/ , the Perl Home Page. |
| 1051 | |
| 1052 | If you believe you have an unreported bug, please run the B<perlbug> |
| 1053 | program included with your release. Be sure to trim your bug down |
| 1054 | to a tiny but sufficient test case. Your bug report, along with the |
| 1055 | output of C<perl -V>, will be sent off to perlbug@perl.org to be |
| 1056 | analysed by the Perl porting team. |
| 1057 | |
| 1058 | =head1 SEE ALSO |
| 1059 | |
| 1060 | The F<Changes> file for exhaustive details on what changed. |
| 1061 | |
| 1062 | The F<INSTALL> file for how to build Perl. |
| 1063 | |
| 1064 | The F<README> file for general stuff. |
| 1065 | |
| 1066 | The F<Artistic> and F<Copying> files for copyright information. |
| 1067 | |
| 1068 | =head1 HISTORY |
| 1069 | |
| 1070 | Written by Jarkko Hietaniemi <F<jhi@iki.fi>>, with many contributions |
| 1071 | from The Perl Porters and Perl Users submitting feedback and patches. |
| 1072 | |
| 1073 | Send omissions or corrections to <F<perlbug@perl.org>>. |
| 1074 | |
| 1075 | =cut |