| 1 | =head1 NAME |
| 2 | |
| 3 | perldelta - what's new for perl v5.6 (as of v5.005_61) |
| 4 | |
| 5 | =head1 DESCRIPTION |
| 6 | |
| 7 | This is an unsupported alpha release, meant for intrepid Perl developers |
| 8 | only. The included sources may not even build correctly on some platforms. |
| 9 | Subscribing to perl5-porters is the best way to monitor and contribute |
| 10 | to the progress of development releases (see www.perl.org for info). |
| 11 | |
| 12 | This document describes differences between the 5.005 release and this one. |
| 13 | |
| 14 | =head1 Incompatible Changes |
| 15 | |
| 16 | =head2 Perl Source Incompatibilities |
| 17 | |
| 18 | TODO |
| 19 | |
| 20 | =head2 C Source Incompatibilities |
| 21 | |
| 22 | =over 4 |
| 23 | |
| 24 | =item C<PERL_POLLUTE> |
| 25 | |
| 26 | Release 5.005 grandfathered old global symbol names by providing preprocessor |
| 27 | macros for extension source compatibility. As of release 5.6, these |
| 28 | preprocessor definitions are not available by default. You need to explicitly |
| 29 | compile perl with C<-DPERL_POLLUTE> to get these definitions. For |
| 30 | extensions still using the old symbols, this option can be |
| 31 | specified via MakeMaker: |
| 32 | |
| 33 | perl Makefile.PL POLLUTE=1 |
| 34 | |
| 35 | =item C<PERL_IMPLICIT_CONTEXT> |
| 36 | |
| 37 | This new build option provides a set of macros for all API functions |
| 38 | such that an implicit interpreter/thread context argument is passed to |
| 39 | every API function. As a result of this, something like C<sv_setsv(foo,bar)> |
| 40 | amounts to a macro invocation that actually translates to something like |
| 41 | C<Perl_sv_setsv(my_perl,foo,bar)>. While this is generally expected |
| 42 | to not have any significant source compatibility issues, the difference |
| 43 | between a macro and a real function call will need to be considered. |
| 44 | |
| 45 | This means that there B<is> a source compatibility issue as a result of |
| 46 | this if your extensions attempt to use pointers to any of the Perl API |
| 47 | functions. |
| 48 | |
| 49 | Note that the above issue is not relevant to the default build of |
| 50 | Perl, whose interfaces continue to match those of prior versions |
| 51 | (but subject to the other options described here). |
| 52 | |
| 53 | PERL_IMPLICIT_CONTEXT is automatically enabled whenever Perl is built |
| 54 | with one of -Dusethreads, -Dusemultiplicity, or both. |
| 55 | |
| 56 | See L<perlguts/"The Perl API"> for detailed information on the |
| 57 | ramifications of building Perl using this option. |
| 58 | |
| 59 | =item C<PERL_POLLUTE_MALLOC> |
| 60 | |
| 61 | Enabling Perl's malloc in release 5.005 and earlier caused |
| 62 | the namespace of system versions of the malloc family of functions to |
| 63 | be usurped by the Perl versions, since by default they used the |
| 64 | same names. |
| 65 | |
| 66 | Besides causing problems on platforms that do not allow these functions to |
| 67 | be cleanly replaced, this also meant that the system versions could not |
| 68 | be called in programs that used Perl's malloc. Previous versions of Perl |
| 69 | have allowed this behaviour to be suppressed with the HIDEMYMALLOC and |
| 70 | EMBEDMYMALLOC preprocessor definitions. |
| 71 | |
| 72 | As of release 5.6, Perl's malloc family of functions have default names |
| 73 | distinct from the system versions. You need to explicitly compile perl with |
| 74 | C<-DPERL_POLLUTE_MALLOC> to get the older behaviour. HIDEMYMALLOC |
| 75 | and EMBEDMYMALLOC have no effect, since the behaviour they enabled is now |
| 76 | the default. |
| 77 | |
| 78 | Note that these functions do B<not> constitute Perl's memory allocation API. |
| 79 | See L<perlguts/"Memory Allocation"> for further information about that. |
| 80 | |
| 81 | =item C<PL_na> and C<dTHR> Issues |
| 82 | |
| 83 | The C<PL_na> global is now thread local, so a C<dTHR> declaration is needed |
| 84 | in the scope in which the global appears. XSUBs should handle this automatically, |
| 85 | but if you have used C<PL_na> in support functions, you either need to |
| 86 | change the C<PL_na> to a local variable (which is recommended), or put in |
| 87 | a C<dTHR>. |
| 88 | |
| 89 | =back |
| 90 | |
| 91 | =head2 Compatible C Source API Changes |
| 92 | |
| 93 | =over |
| 94 | |
| 95 | =item C<PATCHLEVEL> is now C<PERL_VERSION> |
| 96 | |
| 97 | The cpp macros C<PERL_REVISION>, C<PERL_VERSION>, and C<PERL_SUBVERSION> |
| 98 | are now available by default from perl.h, and reflect the base revision, |
| 99 | patchlevel, and subversion respectively. C<PERL_REVISION> had no |
| 100 | prior equivalent, while C<PERL_VERSION> and C<PERL_SUBVERSION> were |
| 101 | previously available as C<PATCHLEVEL> and C<SUBVERSION>. |
| 102 | |
| 103 | The new names cause less pollution of the B<cpp> namespace and reflect what |
| 104 | the numbers have come to stand for in common practice. For compatibility, |
| 105 | the old names are still supported when F<patchlevel.h> is explicitly |
| 106 | included (as required before), so there is no source incompatibility |
| 107 | from the change. |
| 108 | |
| 109 | =back |
| 110 | |
| 111 | =head2 Binary Incompatibilities |
| 112 | |
| 113 | The default build of this release is binary compatible with the 5.005 |
| 114 | release or its maintenance versions. |
| 115 | |
| 116 | The usethreads or usemultiplicity builds are B<not> binary compatible |
| 117 | with the corresponding builds in 5.005. |
| 118 | |
| 119 | =head1 Core Changes |
| 120 | |
| 121 | =head2 Unicode and UTF-8 support |
| 122 | |
| 123 | Perl can optionally use UTF-8 as its internal representation for character |
| 124 | strings. The C<use utf8> pragma enables this support in the current lexical |
| 125 | scope. See L<utf8> for more information. |
| 126 | |
| 127 | =head2 Lexically scoped warning categories |
| 128 | |
| 129 | You can now control the granularity of warnings emitted by perl at a finer |
| 130 | level using the C<use warnings> pragma. See L<warnings> and L<perllexwarn> |
| 131 | for details. |
| 132 | |
| 133 | =head2 Binary numbers supported |
| 134 | |
| 135 | Binary numbers are now supported as literals, in s?printf formats, and |
| 136 | C<oct()>: |
| 137 | |
| 138 | $answer = 0b101010; |
| 139 | printf "The answer is: %b\n", oct("0b101010"); |
| 140 | |
| 141 | =head2 syswrite() ease-of-use |
| 142 | |
| 143 | The length argument of C<syswrite()> is now optional. |
| 144 | |
| 145 | =head2 64-bit support |
| 146 | |
| 147 | All platforms that have 64-bit integers either (a) natively as longs |
| 148 | or ints (b) via special compiler flags (c) using long long are able to |
| 149 | use "quads" (64-integers) as follows: |
| 150 | |
| 151 | =over 4 |
| 152 | |
| 153 | =item constants (decimal, hexadecimal, octal, binary) in the code |
| 154 | |
| 155 | =item arguments to oct() and hex() |
| 156 | |
| 157 | =item arguments to print(), printf() and sprintf() (flag prefixes ll, L, q) |
| 158 | |
| 159 | =item printed as such |
| 160 | |
| 161 | =item pack() and unpack() "q" and "Q" formats |
| 162 | |
| 163 | =item in basic arithmetics: + - * / % |
| 164 | |
| 165 | =item vec() (but see the below note about bit arithmetics) |
| 166 | |
| 167 | =back |
| 168 | |
| 169 | Note that unless you have the case (a) you will have to configure |
| 170 | and compile Perl using the -Duse64bits Configure flag. |
| 171 | |
| 172 | Unfortunately bit arithmetics (&, |, ^, ~, <<, >>) for numbers are not |
| 173 | 64-bit clean, they are explictly forced to be 32-bit. Bit arithmetics |
| 174 | for bit vectors (created by vec()) are not limited in their width. |
| 175 | |
| 176 | Last but not least: note that due to Perl's habit of always using |
| 177 | floating point numbers the quads are still not true integers. |
| 178 | When quads overflow their limits (0...18_446_744_073_709_551_615 unsigned, |
| 179 | -9_223_372_036_854_775_808...9_223_372_036_854_775_807 signed), they |
| 180 | are silently promoted to floating point numbers, after which they will |
| 181 | start losing precision (their lower digits). |
| 182 | |
| 183 | =head2 Large file support |
| 184 | |
| 185 | If you have filesystems that support "large files" (files larger than |
| 186 | 2 gigabytes), you may now also be able to create and access them from |
| 187 | Perl. You have to use Configure -Duselfs. Turning on the large file |
| 188 | support turns on also the 64-bit support, for obvious reasons. |
| 189 | |
| 190 | Note that in addition to requiring a proper file system to do large |
| 191 | files you may also need to adjust your per-process (or your |
| 192 | per-system, or per-process-group, or per-user-group) maximum filesize |
| 193 | limits before running Perl scripts that try to handle large files, |
| 194 | especially if you intend to write such files. |
| 195 | |
| 196 | Finally, in addition to your process/process group maximum filesize |
| 197 | limits, you may have quota limits on your filesystems that stop you |
| 198 | (your user id or your user group id) from using large files. |
| 199 | |
| 200 | Adjusting your process/user/group/file system/operating system limits |
| 201 | is outside the scope of Perl core language. For process limits, you |
| 202 | may try increasing the limits using your shell's limits/limit/ulimit |
| 203 | command before running Perl. The BSD::Resource extension (not |
| 204 | included with the standard Perl distribution) may also be of use, it |
| 205 | offers the getrlimit/setrlimit interface that can be used to adjust |
| 206 | process resource usage limits, including the maximum filesize limit. |
| 207 | |
| 208 | =head2 Long doubles |
| 209 | |
| 210 | In some systems you may be able to use long doubles to enhance the |
| 211 | range of precision of your double precision floating point numbers |
| 212 | (that is, Perl's numbers). Use Configure -Duselongdouble to enable |
| 213 | this support (if it is available). |
| 214 | |
| 215 | =head2 "more bits" |
| 216 | |
| 217 | You can Configure -Dusemorebits to turn on both the 64-bit support |
| 218 | and the long double support. |
| 219 | |
| 220 | =head2 Better syntax checks on parenthesized unary operators |
| 221 | |
| 222 | Expressions such as: |
| 223 | |
| 224 | print defined(&foo,&bar,&baz); |
| 225 | print uc("foo","bar","baz"); |
| 226 | undef($foo,&bar); |
| 227 | |
| 228 | used to be accidentally allowed in earlier versions, and produced |
| 229 | unpredictable behaviour. Some produced ancillary warnings |
| 230 | when used in this way; others silently did the wrong thing. |
| 231 | |
| 232 | The parenthesized forms of most unary operators that expect a single |
| 233 | argument now ensure that they are not called with more than one |
| 234 | argument, making the cases shown above syntax errors. The usual |
| 235 | behaviour of: |
| 236 | |
| 237 | print defined &foo, &bar, &baz; |
| 238 | print uc "foo", "bar", "baz"; |
| 239 | undef $foo, &bar; |
| 240 | |
| 241 | remains unchanged. See L<perlop>. |
| 242 | |
| 243 | =head2 POSIX character class syntax [: :] supported |
| 244 | |
| 245 | For example to match alphabetic characters use /[[:alpha:]]/. |
| 246 | See L<perlre> for details. |
| 247 | |
| 248 | =head2 Improved C<qw//> operator |
| 249 | |
| 250 | The C<qw//> operator is now evaluated at compile time into a true list |
| 251 | instead of being replaced with a run time call to C<split()>. This |
| 252 | removes the confusing misbehaviour of C<qw//> in scalar context, which |
| 253 | had inherited that behaviour from split(). |
| 254 | |
| 255 | Thus: |
| 256 | |
| 257 | $foo = ($bar) = qw(a b c); print "$foo|$bar\n"; |
| 258 | |
| 259 | now correctly prints "3|a", instead of "2|a". |
| 260 | |
| 261 | =head2 pack() format 'Z' supported |
| 262 | |
| 263 | The new format type 'Z' is useful for packing and unpacking null-terminated |
| 264 | strings. See L<perlfunc/"pack">. |
| 265 | |
| 266 | =head2 pack() format modifier '!' supported |
| 267 | |
| 268 | The new format type modifier '!' is useful for packing and unpacking |
| 269 | native shorts, ints, and longs. See L<perlfunc/"pack">. |
| 270 | |
| 271 | =head2 pack() and unpack() support counted strings |
| 272 | |
| 273 | The template character '#' can be used to specify a counted string |
| 274 | type to be packed or unpacked. See L<perlfunc/"pack">. |
| 275 | |
| 276 | =head2 $^X variables may now have names longer than one character |
| 277 | |
| 278 | Formerly, $^X was synonymous with ${"\cX"}, but $^XY was a syntax |
| 279 | error. Now variable names that begin with a control character may be |
| 280 | arbitrarily long. However, for compatibility reasons, these variables |
| 281 | I<must> be written with explicit braces, as C<${^XY}> for example. |
| 282 | C<${^XYZ}> is synonymous with ${"\cXYZ"}. Variable names with more |
| 283 | than one control character, such as C<${^XY^Z}>, are illegal. |
| 284 | |
| 285 | The old syntax has not changed. As before, `^X' may be either a |
| 286 | literal control-X character or the two-character sequence `caret' plus |
| 287 | `X'. When braces are omitted, the variable name stops after the |
| 288 | control character. Thus C<"$^XYZ"> continues to be synonymous with |
| 289 | C<$^X . "YZ"> as before. |
| 290 | |
| 291 | As before, lexical variables may not have names beginning with control |
| 292 | characters. As before, variables whose names begin with a control |
| 293 | character are always forced to be in package `main'. All such variables |
| 294 | are reserved for future extensions, except those that begin with |
| 295 | C<^_>, which may be used by user programs and are guaranteed not to |
| 296 | acquire special meaning in any future version of Perl. |
| 297 | |
| 298 | =head2 C<use attrs> implicit in subroutine attributes |
| 299 | |
| 300 | Formerly, if you wanted to mark a subroutine as being a method call or |
| 301 | as requiring an automatic lock() when it is entered, you had to declare |
| 302 | that with a C<use attrs> pragma in the body of the subroutine. |
| 303 | That can now be accomplished with a declaration syntax, like this: |
| 304 | |
| 305 | sub mymethod : locked, method ; |
| 306 | ... |
| 307 | sub mymethod : locked, method { |
| 308 | ... |
| 309 | } |
| 310 | |
| 311 | F<AutoSplit.pm> and F<SelfLoader.pm> have been updated to keep the attributes |
| 312 | with the stubs they provide. See L<attributes>. |
| 313 | |
| 314 | =head1 Significant bug fixes |
| 315 | |
| 316 | =head2 E<lt>HANDLEE<gt> on empty files |
| 317 | |
| 318 | With C<$/> set to C<undef>, slurping an empty file returns a string of |
| 319 | zero length (instead of C<undef>, as it used to) the first time the |
| 320 | HANDLE is read. Further reads yield C<undef>. |
| 321 | |
| 322 | This means that the following will append "foo" to an empty file (it used |
| 323 | to do nothing): |
| 324 | |
| 325 | perl -0777 -pi -e 's/^/foo/' empty_file |
| 326 | |
| 327 | The behaviour of: |
| 328 | |
| 329 | perl -pi -e 's/^/foo/' empty_file |
| 330 | |
| 331 | is unchanged (it continues to leave the file empty). |
| 332 | |
| 333 | =head2 C<eval '...'> improvements |
| 334 | |
| 335 | Line numbers (as reflected by caller() and most diagnostics) within |
| 336 | C<eval '...'> were often incorrect when here documents were involved. |
| 337 | This has been corrected. |
| 338 | |
| 339 | Lexical lookups for variables appearing in C<eval '...'> within |
| 340 | functions that were themselves called within an C<eval '...'> were |
| 341 | searching the wrong place for lexicals. The lexical search now |
| 342 | correctly ends at the subroutine's block boundary. |
| 343 | |
| 344 | Parsing of here documents used to be flawed when they appeared as |
| 345 | the replacement expression in C<eval 's/.../.../e'>. This has |
| 346 | been fixed. |
| 347 | |
| 348 | =head2 Automatic flushing of output buffers |
| 349 | |
| 350 | fork(), exec(), system(), qx//, and pipe open()s now flush buffers |
| 351 | of all files opened for output when the operation |
| 352 | was attempted. This mostly eliminates confusing |
| 353 | buffering mishaps suffered by users unaware of how Perl internally |
| 354 | handles I/O. |
| 355 | |
| 356 | =head2 Better diagnostics on meaningless filehandle operations |
| 357 | |
| 358 | Constructs such as C<open(E<lt>FHE<gt>)> and C<close(E<lt>FHE<gt>)> |
| 359 | are compile time errors. Attempting to read from filehandles that |
| 360 | were opened only for writing will now produce warnings (just as |
| 361 | writing to read-only filehandles does). |
| 362 | |
| 363 | =head2 Buffered data discarded from input filehandle when dup'ed. |
| 364 | |
| 365 | C<open(NEW, "E<lt>&OLD")> now discards any data that was previously |
| 366 | read and buffered in C<OLD>. The next read operation on C<NEW> will |
| 367 | return the same data as the corresponding operation on C<OLD>. |
| 368 | Formerly, it would have returned the data from the start of the |
| 369 | following disk block instead. |
| 370 | |
| 371 | =head1 Supported Platforms |
| 372 | |
| 373 | =over 4 |
| 374 | |
| 375 | =item * |
| 376 | |
| 377 | VM/ESA is now supported. |
| 378 | |
| 379 | =item * |
| 380 | |
| 381 | Siemens BS2000 is now supported under the POSIX Shell. |
| 382 | |
| 383 | =item * |
| 384 | |
| 385 | The Mach CThreads (NEXTSTEP, OPENSTEP) are now supported by the Thread |
| 386 | extension. |
| 387 | |
| 388 | =item * |
| 389 | |
| 390 | GNU/Hurd is now supported. |
| 391 | |
| 392 | =item * |
| 393 | |
| 394 | Rhapsody is now supported. |
| 395 | |
| 396 | =item * |
| 397 | |
| 398 | EPOC is is now supported (on Psion 5). |
| 399 | |
| 400 | =back |
| 401 | |
| 402 | =head1 New tests |
| 403 | |
| 404 | =over 4 |
| 405 | |
| 406 | =item lib/attrs |
| 407 | |
| 408 | Compatibility tests for C<sub : attrs> vs the older C<use attrs>. |
| 409 | |
| 410 | =item lib/io_const |
| 411 | |
| 412 | IO constants (SEEK_*, _IO*). |
| 413 | |
| 414 | =item lib/io_dir |
| 415 | |
| 416 | Directory-related IO methods (new, read, close, rewind, tied delete). |
| 417 | |
| 418 | =item lib/io_multihomed |
| 419 | |
| 420 | INET sockets with multi-homed hosts. |
| 421 | |
| 422 | =item lib/io_poll |
| 423 | |
| 424 | IO poll(). |
| 425 | |
| 426 | =item lib/io_unix |
| 427 | |
| 428 | UNIX sockets. |
| 429 | |
| 430 | =item op/attrs |
| 431 | |
| 432 | Regression tests for C<my ($x,@y,%z) : attrs> and <sub : attrs>. |
| 433 | |
| 434 | =item op/filetest |
| 435 | |
| 436 | File test operators. |
| 437 | |
| 438 | =item op/lex_assign |
| 439 | |
| 440 | Verify operations that access pad objects (lexicals and temporaries). |
| 441 | |
| 442 | =back |
| 443 | |
| 444 | =head1 Modules and Pragmata |
| 445 | |
| 446 | =head2 Modules |
| 447 | |
| 448 | =over 4 |
| 449 | |
| 450 | =item attributes |
| 451 | |
| 452 | While used internally by Perl as a pragma, this module also |
| 453 | provides a way to fetch subroutine and variable attributes. |
| 454 | See L<attributes>. |
| 455 | |
| 456 | =item ByteLoader |
| 457 | |
| 458 | The ByteLoader is a dedication extension to generate and run |
| 459 | Perl bytecode. See L<ByteLoader>. |
| 460 | |
| 461 | =item B |
| 462 | |
| 463 | The Perl Compiler suite has been extensively reworked for this |
| 464 | release. |
| 465 | |
| 466 | =item Devel::DProf |
| 467 | |
| 468 | Devel::DProf, a Perl source code profiler has been added. |
| 469 | |
| 470 | =item Dumpvalue |
| 471 | |
| 472 | Added Dumpvalue module provides screen dumps of Perl data. |
| 473 | |
| 474 | =item Benchmark |
| 475 | |
| 476 | You can now run tests for I<n> seconds instead of guessing the right |
| 477 | number of tests to run: e.g. timethese(-5, ...) will run each |
| 478 | code for at least 5 CPU seconds. Zero as the "number of repetitions" |
| 479 | means "for at least 3 CPU seconds". The output format has also |
| 480 | changed. For example: |
| 481 | |
| 482 | use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}}) |
| 483 | |
| 484 | will now output something like this: |
| 485 | |
| 486 | Benchmark: running a, b, each for at least 5 CPU seconds... |
| 487 | a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516) |
| 488 | b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686) |
| 489 | |
| 490 | New features: "each for at least N CPU seconds...", "wallclock secs", |
| 491 | and the "@ operations/CPU second (n=operations)". |
| 492 | |
| 493 | =item Devel::Peek |
| 494 | |
| 495 | The Devel::Peek module provides access to the internal representation |
| 496 | of Perl variables and data. It is a data debugging tool for the XS programmer. |
| 497 | |
| 498 | =item Fcntl |
| 499 | |
| 500 | More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for |
| 501 | large (more than 4G) file access (64-bit support is not yet |
| 502 | working, though, so no need to get overly excited), Free/Net/OpenBSD |
| 503 | locking behaviour flags F_FLOCK, F_POSIX, Linux F_SHLCK, and |
| 504 | O_ACCMODE: the mask of O_RDONLY, O_WRONLY, and O_RDWR. |
| 505 | |
| 506 | =item File::Spec |
| 507 | |
| 508 | New methods have been added to the File::Spec module: devnull() returns |
| 509 | the name of the null device (/dev/null on Unix) and tmpdir() the name of |
| 510 | the temp directory (normally /tmp on Unix). There are now also methods |
| 511 | to convert between absolute and relative filenames: abs2rel() and |
| 512 | rel2abs(). For compatibility with operating systems that specify volume |
| 513 | names in file paths, the splitpath(), splitdir(), and catdir() methods |
| 514 | have been added. |
| 515 | |
| 516 | =item File::Spec::Functions |
| 517 | |
| 518 | The new File::Spec::Functions modules provides a function interface |
| 519 | to the File::Spec module. Allows shorthand |
| 520 | |
| 521 | $fullname = catfile($dir1, $dir2, $file); |
| 522 | |
| 523 | instead of |
| 524 | |
| 525 | $fullname = File::Spec->catfile($dir1, $dir2, $file); |
| 526 | |
| 527 | =item Math::BigInt |
| 528 | |
| 529 | The logical operations C<E<lt>E<lt>>, C<E<gt>E<gt>>, C<&>, C<|>, |
| 530 | and C<~> are now supported on bigints. |
| 531 | |
| 532 | =item Math::Complex |
| 533 | |
| 534 | The accessor methods Re, Im, arg, abs, rho, and theta can now also |
| 535 | act as mutators (accessor $z->Re(), mutator $z->Re(3)). |
| 536 | |
| 537 | =item Math::Trig |
| 538 | |
| 539 | A little bit of radial trigonometry (cylindrical and spherical), |
| 540 | radial coordinate conversions, and the great circle distance were added. |
| 541 | |
| 542 | =item SDBM_File |
| 543 | |
| 544 | An EXISTS method has been added to this module (and sdbm_exists() has |
| 545 | been added to the underlying sdbm library), so one can now call exists |
| 546 | on an SDBM_File tied hash and get the correct result, rather than a |
| 547 | runtime error. |
| 548 | |
| 549 | =item Time::Local |
| 550 | |
| 551 | The timelocal() and timegm() functions used to silently return bogus |
| 552 | results when the date exceeded the machine's integer range. They |
| 553 | now consistently croak() if the date falls in an unsupported range-- |
| 554 | but on the other hand they now accept "out-of-limits" day-of-month |
| 555 | to make "Julian date" conversions easier. |
| 556 | |
| 557 | =item Win32 |
| 558 | |
| 559 | The error return value in list context has been changed for all functions |
| 560 | that return a list of values. Previously these functions returned a list |
| 561 | with a single element C<undef> if an error occurred. Now these functions |
| 562 | return the empty list in these situations. This applies to the following |
| 563 | functions: |
| 564 | |
| 565 | Win32::FsType |
| 566 | Win32::GetOSVersion |
| 567 | |
| 568 | The remaining functions are unchanged and continue to return C<undef> on |
| 569 | error even in list context. |
| 570 | |
| 571 | The Win32::SetLastError(ERROR) function has been added as a complement |
| 572 | to the Win32::GetLastError() function. |
| 573 | |
| 574 | The new Win32::GetFullPathName(FILENAME) returns the full absolute |
| 575 | pathname for FILENAME in scalar context. In list context it returns |
| 576 | a two-element list containing the fully qualified directory name and |
| 577 | the filename. |
| 578 | |
| 579 | =item DBM Filters |
| 580 | |
| 581 | A new feature called "DBM Filters" has been added to all the |
| 582 | DBM modules--DB_File, GDBM_File, NDBM_File, ODBM_File, and SDBM_File. |
| 583 | DBM Filters add four new methods to each DBM module: |
| 584 | |
| 585 | filter_store_key |
| 586 | filter_store_value |
| 587 | filter_fetch_key |
| 588 | filter_fetch_value |
| 589 | |
| 590 | These can be used to filter key-value pairs before the pairs are |
| 591 | written to the database or just after they are read from the database. |
| 592 | See L<perldbmfilter> for further information. |
| 593 | |
| 594 | =back |
| 595 | |
| 596 | =head2 Pragmata |
| 597 | |
| 598 | C<use attrs> is now obsolescent, and is only provided for |
| 599 | backward-compatibility. It's been replaced by the C<sub : attributes> |
| 600 | syntax. See L<perlsub/"Subroutine Attributes"> and L<attributes>. |
| 601 | |
| 602 | C<use utf8> to enable UTF-8 and Unicode support. |
| 603 | |
| 604 | C<use caller 'encoding'> allows modules to inherit pragmatic attributes |
| 605 | from the caller's context. C<encoding> is currently the only supported |
| 606 | attribute. |
| 607 | |
| 608 | Lexical warnings pragma, C<use warnings;>, to control optional warnings. |
| 609 | |
| 610 | C<use filetest> to control the behaviour of filetests (C<-r> C<-w> ...). |
| 611 | Currently only one subpragma implemented, "use filetest 'access';", |
| 612 | that enables the use of access(2) or equivalent to check |
| 613 | permissions instead of using stat(2) as usual. This matters |
| 614 | in filesystems where there are ACLs (access control lists): the |
| 615 | stat(2) might lie, but access(2) knows better. |
| 616 | |
| 617 | =head1 Utility Changes |
| 618 | |
| 619 | Todo. |
| 620 | |
| 621 | =head1 Documentation Changes |
| 622 | |
| 623 | =over 4 |
| 624 | |
| 625 | =item perlopentut.pod |
| 626 | |
| 627 | A tutorial on using open() effectively. |
| 628 | |
| 629 | =item perlreftut.pod |
| 630 | |
| 631 | A tutorial that introduces the essentials of references. |
| 632 | |
| 633 | =item perltootc.pod |
| 634 | |
| 635 | A tutorial on managing class data for object modules. |
| 636 | |
| 637 | =back |
| 638 | |
| 639 | =head1 New Diagnostics |
| 640 | |
| 641 | =item "my sub" not yet implemented |
| 642 | |
| 643 | (F) Lexically scoped subroutines are not yet implemented. Don't try that |
| 644 | yet. |
| 645 | |
| 646 | =item %s package attribute may clash with future reserved word: %s |
| 647 | |
| 648 | (W) A lowercase attribute name was used that had a package-specific handler. |
| 649 | That name might have a meaning to Perl itself some day, even though it |
| 650 | doesn't yet. Perhaps you should use a mixed-case attribute name, instead. |
| 651 | See L<attributes>. |
| 652 | |
| 653 | =item /%s/: Unrecognized escape \\%c passed through |
| 654 | |
| 655 | (W) You used a backslash-character combination which is not recognized |
| 656 | by Perl. This combination appears in an interpolated variable or a |
| 657 | C<'>-delimited regular expression. |
| 658 | |
| 659 | =item Filehandle %s opened only for output |
| 660 | |
| 661 | (W) You tried to read from a filehandle opened only for writing. If you |
| 662 | intended it to be a read-write filehandle, you needed to open it with |
| 663 | "+E<lt>" or "+E<gt>" or "+E<gt>E<gt>" instead of with "E<lt>" or nothing. If |
| 664 | you intended only to read from the file, use "E<lt>". See |
| 665 | L<perlfunc/open>. |
| 666 | |
| 667 | =item Invalid %s attribute: %s |
| 668 | |
| 669 | The indicated attribute for a subroutine or variable was not recognized |
| 670 | by Perl or by a user-supplied handler. See L<attributes>. |
| 671 | |
| 672 | =item Invalid %s attributes: %s |
| 673 | |
| 674 | The indicated attributes for a subroutine or variable were not recognized |
| 675 | by Perl or by a user-supplied handler. See L<attributes>. |
| 676 | |
| 677 | =item Invalid separator character %s in attribute list |
| 678 | |
| 679 | (F) Something other than a comma or whitespace was seen between the |
| 680 | elements of an attribute list. If the previous attribute |
| 681 | had a parenthesised parameter list, perhaps that list was terminated |
| 682 | too soon. See L<attributes>. |
| 683 | |
| 684 | =item Missing command in piped open |
| 685 | |
| 686 | (W) You used the C<open(FH, "| command")> or C<open(FH, "command |")> |
| 687 | construction, but the command was missing or blank. |
| 688 | |
| 689 | =item Missing name in "my sub" |
| 690 | |
| 691 | (F) The reserved syntax for lexically scoped subroutines requires that they |
| 692 | have a name with which they can be found. |
| 693 | |
| 694 | =item Unrecognized escape \\%c passed through |
| 695 | |
| 696 | (W) You used a backslash-character combination which is not recognized |
| 697 | by Perl. |
| 698 | |
| 699 | =item Unterminated attribute parameter in attribute list |
| 700 | |
| 701 | (F) The lexer saw an opening (left) parenthesis character while parsing an |
| 702 | attribute list, but the matching closing (right) parenthesis |
| 703 | character was not found. You may need to add (or remove) a backslash |
| 704 | character to get your parentheses to balance. See L<attributes>. |
| 705 | |
| 706 | =item Unterminated attribute list |
| 707 | |
| 708 | (F) The lexer found something other than a simple identifier at the start |
| 709 | of an attribute, and it wasn't a semicolon or the start of a |
| 710 | block. Perhaps you terminated the parameter list of the previous attribute |
| 711 | too soon. See L<attributes>. |
| 712 | |
| 713 | =item defined(@array) is deprecated |
| 714 | |
| 715 | (D) defined() is not usually useful on arrays because it checks for an |
| 716 | undefined I<scalar> value. If you want to see if the array is empty, |
| 717 | just use C<if (@array) { # not empty }> for example. |
| 718 | |
| 719 | =item defined(%hash) is deprecated |
| 720 | |
| 721 | (D) defined() is not usually useful on hashes because it checks for an |
| 722 | undefined I<scalar> value. If you want to see if the hash is empty, |
| 723 | just use C<if (%hash) { # not empty }> for example. |
| 724 | |
| 725 | =item Invalid separator character %s in subroutine attribute list |
| 726 | |
| 727 | (F) Something other than a comma or whitespace was seen between the |
| 728 | elements of a subroutine attribute list. If the previous attribute |
| 729 | had a parenthesised parameter list, perhaps that list was terminated |
| 730 | too soon. |
| 731 | |
| 732 | =item Possible Y2K bug: %s |
| 733 | |
| 734 | (W) You are concatenating the number 19 with another number, which |
| 735 | could be a potential Year 2000 problem. |
| 736 | |
| 737 | =item Unterminated attribute parameter in subroutine attribute list |
| 738 | |
| 739 | (F) The lexer saw an opening (left) parenthesis character while parsing a |
| 740 | subroutine attribute list, but the matching closing (right) parenthesis |
| 741 | character was not found. You may need to add (or remove) a backslash |
| 742 | character to get your parentheses to balance. |
| 743 | |
| 744 | =item Unterminated subroutine attribute list |
| 745 | |
| 746 | (F) The lexer found something other than a simple identifier at the start |
| 747 | of a subroutine attribute, and it wasn't a semicolon or the start of a |
| 748 | block. Perhaps you terminated the parameter list of the previous attribute |
| 749 | too soon. |
| 750 | |
| 751 | =item /%s/ should probably be written as "%s" |
| 752 | |
| 753 | (W) You have used a pattern where Perl expected to find a string, |
| 754 | like in the first argument to C<join>. Perl will treat the true |
| 755 | or false result of matching the pattern against $_ as the string, |
| 756 | which is probably not what you had in mind. |
| 757 | |
| 758 | =head1 Obsolete Diagnostics |
| 759 | |
| 760 | Todo. |
| 761 | |
| 762 | =head1 Configuration Changes |
| 763 | |
| 764 | =head2 installusrbinperl |
| 765 | |
| 766 | You can use "Configure -Uinstallusrbinperl" which causes installperl |
| 767 | to skip installing perl also as /usr/bin/perl. This is useful if you |
| 768 | prefer not to modify /usr/bin for some reason or another but harmful |
| 769 | because many scripts assume to find Perl in /usr/bin/perl. |
| 770 | |
| 771 | =head2 SOCKS support |
| 772 | |
| 773 | You can use "Configure -Dusesocks" which causes Perl to probe |
| 774 | for the SOCKS proxy protocol library, http://www.socks.nec.com/ |
| 775 | |
| 776 | =head2 -A flag |
| 777 | |
| 778 | You can "post-edit" the Configure variables using the Configure -A |
| 779 | flag. The editing happens immediately after the platform specific |
| 780 | hints files have been processed but before the actual configuration |
| 781 | process starts. Run Configure -h to find out the full -A syntax. |
| 782 | |
| 783 | =head1 BUGS |
| 784 | |
| 785 | If you find what you think is a bug, you might check the headers of |
| 786 | articles recently posted to the comp.lang.perl.misc newsgroup. |
| 787 | There may also be information at http://www.perl.com/perl/, the Perl |
| 788 | Home Page. |
| 789 | |
| 790 | If you believe you have an unreported bug, please run the B<perlbug> |
| 791 | program included with your release. Make sure to trim your bug down |
| 792 | to a tiny but sufficient test case. Your bug report, along with the |
| 793 | output of C<perl -V>, will be sent off to perlbug@perl.com to be |
| 794 | analysed by the Perl porting team. |
| 795 | |
| 796 | =head1 SEE ALSO |
| 797 | |
| 798 | The F<Changes> file for exhaustive details on what changed. |
| 799 | |
| 800 | The F<INSTALL> file for how to build Perl. |
| 801 | |
| 802 | The F<README> file for general stuff. |
| 803 | |
| 804 | The F<Artistic> and F<Copying> files for copyright information. |
| 805 | |
| 806 | =head1 HISTORY |
| 807 | |
| 808 | Written by Gurusamy Sarathy <F<gsar@umich.edu>>, with many contributions |
| 809 | from The Perl Porters. |
| 810 | |
| 811 | Send omissions or corrections to <F<perlbug@perl.com>>. |
| 812 | |
| 813 | =cut |