| 1 | =head1 NAME |
| 2 | |
| 3 | perldelta - what's new for perl v5.6 (as of v5.005_62) |
| 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 | Beware that any new warnings that have been added are B<not> considered |
| 19 | incompatible changes. |
| 20 | |
| 21 | Since all new warnings must be explicitly requested via the C<-w> |
| 22 | switch or the C<warnings> pragma, it is ultimately the programmer's |
| 23 | responsibility to ensure that warnings are enabled judiciously. |
| 24 | |
| 25 | =over 4 |
| 26 | |
| 27 | =item Treatment of list slices of undef has changed |
| 28 | |
| 29 | When taking a slice of a literal list (as opposed to a slice of |
| 30 | an array or hash), Perl used to return an empty list if the |
| 31 | result happened to be composed of all undef values. |
| 32 | |
| 33 | The new behavior is to produce an empty list if (and only if) |
| 34 | the original list was empty. Consider the following example: |
| 35 | |
| 36 | @a = (1,undef,undef,2)[2,1,2]; |
| 37 | |
| 38 | The old behavior would have resulted in @a having no elements. |
| 39 | The new behavior ensures it has three undefined elements. |
| 40 | |
| 41 | Note in particular that the behavior of slices of the following |
| 42 | cases remains unchanged: |
| 43 | |
| 44 | @a = ()[1,2]; |
| 45 | @a = (getpwent)[7,0]; |
| 46 | @a = (anything_returning_empty_list())[2,1,2]; |
| 47 | @a = @b[2,1,2]; |
| 48 | @a = @c{'a','b','c'}; |
| 49 | |
| 50 | See L<perldata>. |
| 51 | |
| 52 | =item Possibly changed pseudo-random number generator |
| 53 | |
| 54 | In 5.005_0x and earlier, perl's rand() function used the C library |
| 55 | rand(3) function. As of 5.005_52, Configure tests for drand48(), |
| 56 | random(), and rand() (in that order) and picks the first one it finds. |
| 57 | Perl programs that depend on reproducing a specific set of pseudo-random |
| 58 | numbers will now likely produce different output. |
| 59 | |
| 60 | =item Hashing function for hash keys has changed |
| 61 | |
| 62 | Perl hashes are not order preserving. The apparently random order |
| 63 | encountered when iterating on the contents of a hash is determined |
| 64 | by the hashing algorithm used. To improve the distribution of lower |
| 65 | bits in the hashed value, the algorithm has changed slightly as of |
| 66 | 5.005_52. When iterating over hashes, this may yield a random order |
| 67 | that is B<different> from that of previous versions. |
| 68 | |
| 69 | =item C<undef> fails on read only values |
| 70 | |
| 71 | Using the C<undef> operator on a readonly value (such as $1) has |
| 72 | the same effect as assigning C<undef> to the readonly value--it |
| 73 | throws an exception. |
| 74 | |
| 75 | =item Close-on-exec bit may be set on pipe() handles |
| 76 | |
| 77 | On systems that support a close-on-exec flag on filehandles, the |
| 78 | flag will be set for any handles created by pipe(), if that is |
| 79 | warranted by the value of $^F that may be in effect. Earlier |
| 80 | versions neglected to set the flag for handles created with |
| 81 | pipe(). See L<perlfunc/pipe> and L<perlvar/$^F>. |
| 82 | |
| 83 | =item Writing C<"$$1"> to mean C<"${$}1"> is unsupported |
| 84 | |
| 85 | Perl 5.004 deprecated the interpretation of C<$$1> and |
| 86 | similar within interpolated strings to mean C<$$ . "1">, |
| 87 | but still allowed it. |
| 88 | |
| 89 | In Perl 5.6 and later, C<"$$1"> always means C<"${$1}">. |
| 90 | |
| 91 | =item values(%h) and C<\(%h)> operate on aliases to values, not copies |
| 92 | |
| 93 | each(), values() and hashes in a list context return the actual |
| 94 | values in the hash, instead of copies (as they used to in earlier |
| 95 | versions). Typical idioms for using these constructs copy the |
| 96 | returned values, but this is can make a significant difference when |
| 97 | creating references to the returned values. |
| 98 | |
| 99 | Keys in the hash are still returned as copies when iterating on |
| 100 | a hash. |
| 101 | |
| 102 | =item vec(EXPR,OFFSET,BITS) enforces powers-of-two BITS |
| 103 | |
| 104 | vec() generates a run-time error if the BITS argument is not |
| 105 | a valid power-of-two integer. |
| 106 | |
| 107 | =item Text of some diagnostic output has changed |
| 108 | |
| 109 | Most references to internal Perl operations in diagnostics |
| 110 | have been changed to be more descriptive. This may be an |
| 111 | issue for programs that may incorrectly rely on the exact |
| 112 | text of diagnostics for proper functioning. |
| 113 | |
| 114 | =item C<%@> has been removed |
| 115 | |
| 116 | The undocumented special variable C<%@> that used to accumulate |
| 117 | "background" errors (such as those that happen in DESTROY()) |
| 118 | has been removed, because it could potentially result in memory |
| 119 | leaks. |
| 120 | |
| 121 | =back |
| 122 | |
| 123 | =head2 C Source Incompatibilities |
| 124 | |
| 125 | =over 4 |
| 126 | |
| 127 | =item C<PERL_POLLUTE> |
| 128 | |
| 129 | Release 5.005 grandfathered old global symbol names by providing preprocessor |
| 130 | macros for extension source compatibility. As of release 5.6, these |
| 131 | preprocessor definitions are not available by default. You need to explicitly |
| 132 | compile perl with C<-DPERL_POLLUTE> to get these definitions. For |
| 133 | extensions still using the old symbols, this option can be |
| 134 | specified via MakeMaker: |
| 135 | |
| 136 | perl Makefile.PL POLLUTE=1 |
| 137 | |
| 138 | =item C<PERL_IMPLICIT_CONTEXT> |
| 139 | |
| 140 | This new build option provides a set of macros for all API functions |
| 141 | such that an implicit interpreter/thread context argument is passed to |
| 142 | every API function. As a result of this, something like C<sv_setsv(foo,bar)> |
| 143 | amounts to a macro invocation that actually translates to something like |
| 144 | C<Perl_sv_setsv(my_perl,foo,bar)>. While this is generally expected |
| 145 | to not have any significant source compatibility issues, the difference |
| 146 | between a macro and a real function call will need to be considered. |
| 147 | |
| 148 | This means that there B<is> a source compatibility issue as a result of |
| 149 | this if your extensions attempt to use pointers to any of the Perl API |
| 150 | functions. |
| 151 | |
| 152 | Note that the above issue is not relevant to the default build of |
| 153 | Perl, whose interfaces continue to match those of prior versions |
| 154 | (but subject to the other options described here). |
| 155 | |
| 156 | PERL_IMPLICIT_CONTEXT is automatically enabled whenever Perl is built |
| 157 | with one of -Dusethreads, -Dusemultiplicity, or both. |
| 158 | |
| 159 | See L<perlguts/"The Perl API"> for detailed information on the |
| 160 | ramifications of building Perl using this option. |
| 161 | |
| 162 | =item C<PERL_POLLUTE_MALLOC> |
| 163 | |
| 164 | Enabling Perl's malloc in release 5.005 and earlier caused |
| 165 | the namespace of system versions of the malloc family of functions to |
| 166 | be usurped by the Perl versions, since by default they used the |
| 167 | same names. |
| 168 | |
| 169 | Besides causing problems on platforms that do not allow these functions to |
| 170 | be cleanly replaced, this also meant that the system versions could not |
| 171 | be called in programs that used Perl's malloc. Previous versions of Perl |
| 172 | have allowed this behaviour to be suppressed with the HIDEMYMALLOC and |
| 173 | EMBEDMYMALLOC preprocessor definitions. |
| 174 | |
| 175 | As of release 5.6, Perl's malloc family of functions have default names |
| 176 | distinct from the system versions. You need to explicitly compile perl with |
| 177 | C<-DPERL_POLLUTE_MALLOC> to get the older behaviour. HIDEMYMALLOC |
| 178 | and EMBEDMYMALLOC have no effect, since the behaviour they enabled is now |
| 179 | the default. |
| 180 | |
| 181 | Note that these functions do B<not> constitute Perl's memory allocation API. |
| 182 | See L<perlguts/"Memory Allocation"> for further information about that. |
| 183 | |
| 184 | =item C<PL_na> and C<dTHR> Issues |
| 185 | |
| 186 | The C<PL_na> global is now thread local, so a C<dTHR> declaration is needed |
| 187 | in the scope in which the global appears. XSUBs should handle this automatically, |
| 188 | but if you have used C<PL_na> in support functions, you either need to |
| 189 | change the C<PL_na> to a local variable (which is recommended), or put in |
| 190 | a C<dTHR>. |
| 191 | |
| 192 | =back |
| 193 | |
| 194 | =head2 Compatible C Source API Changes |
| 195 | |
| 196 | =over |
| 197 | |
| 198 | =item C<PATCHLEVEL> is now C<PERL_VERSION> |
| 199 | |
| 200 | The cpp macros C<PERL_REVISION>, C<PERL_VERSION>, and C<PERL_SUBVERSION> |
| 201 | are now available by default from perl.h, and reflect the base revision, |
| 202 | patchlevel, and subversion respectively. C<PERL_REVISION> had no |
| 203 | prior equivalent, while C<PERL_VERSION> and C<PERL_SUBVERSION> were |
| 204 | previously available as C<PATCHLEVEL> and C<SUBVERSION>. |
| 205 | |
| 206 | The new names cause less pollution of the B<cpp> namespace and reflect what |
| 207 | the numbers have come to stand for in common practice. For compatibility, |
| 208 | the old names are still supported when F<patchlevel.h> is explicitly |
| 209 | included (as required before), so there is no source incompatibility |
| 210 | from the change. |
| 211 | |
| 212 | =item Support for C++ exceptions |
| 213 | |
| 214 | change#3386, also needs perlguts documentation |
| 215 | [TODO - Chip Salzenberg <chip@perlsupport.com>] |
| 216 | |
| 217 | =back |
| 218 | |
| 219 | =head2 Binary Incompatibilities |
| 220 | |
| 221 | The default build of this release is binary compatible with the 5.005 |
| 222 | release or its maintenance versions. |
| 223 | |
| 224 | The usethreads or usemultiplicity builds are B<not> binary compatible |
| 225 | with the corresponding builds in 5.005. |
| 226 | |
| 227 | =head1 Installation and Configuration Improvements |
| 228 | |
| 229 | =head2 New Configure flags |
| 230 | |
| 231 | The following new flags may be enabled on the Configure command line |
| 232 | by running Configure with C<-Dflag>. |
| 233 | |
| 234 | usemultiplicity |
| 235 | |
| 236 | uselongdouble |
| 237 | usemorebits |
| 238 | uselargefiles |
| 239 | |
| 240 | =head2 -Dusethreads and -Duse64bits now more daring |
| 241 | |
| 242 | The Configure options enabling the use of threads and the use of |
| 243 | 64-bitness are now more daring in the sense that they no more have |
| 244 | an explicit list of operating systems of known threads/64-bit |
| 245 | capabilities. In other words: if your operating system has the |
| 246 | necessary APIs, you should be able just to go ahead and use them. |
| 247 | See also L<"64-bit support">. |
| 248 | |
| 249 | =head2 Long Doubles |
| 250 | |
| 251 | Some platforms have "long doubles", floating point numbers of even |
| 252 | larger range than ordinary "doubles". To enable using ng doubles for |
| 253 | Perl's scalars, use -Duselongdouble. |
| 254 | |
| 255 | =head2 -Dusemorebits |
| 256 | |
| 257 | You can enable both -Duse64bits and -Dlongdouble by -Dusemorebits. |
| 258 | See also L<"64-bit support">. |
| 259 | |
| 260 | =head2 -Duselargefiles |
| 261 | |
| 262 | Some platforms support large files, files larger than two gigabytes. |
| 263 | See L<"Large file support"> for more information. |
| 264 | |
| 265 | =head2 installusrbinperl |
| 266 | |
| 267 | You can use "Configure -Uinstallusrbinperl" which causes installperl |
| 268 | to skip installing perl also as /usr/bin/perl. This is useful if you |
| 269 | prefer not to modify /usr/bin for some reason or another but harmful |
| 270 | because many scripts assume to find Perl in /usr/bin/perl. |
| 271 | |
| 272 | =head2 SOCKS support |
| 273 | |
| 274 | You can use "Configure -Dusesocks" which causes Perl to probe |
| 275 | for the SOCKS proxy protocol library, http://www.socks.nec.com/ |
| 276 | |
| 277 | =head2 C<-A> flag |
| 278 | |
| 279 | You can "post-edit" the Configure variables using the Configure C<-A> |
| 280 | flag. The editing happens immediately after the platform specific |
| 281 | hints files have been processed but before the actual configuration |
| 282 | process starts. Run C<Configure -h> to find out the full C<-A> syntax. |
| 283 | |
| 284 | =head2 New Installation Scheme |
| 285 | |
| 286 | vendorprefix et al |
| 287 | [TODO - Andy Dougherty <doughera@lafcol.lafayette.edu>] |
| 288 | |
| 289 | =head1 Core Changes |
| 290 | |
| 291 | =head2 Unicode and UTF-8 support |
| 292 | |
| 293 | Perl can optionally use UTF-8 as its internal representation for character |
| 294 | strings. The C<utf8> pragma enables this support in the current lexical |
| 295 | scope. See L<utf8> for more information. |
| 296 | |
| 297 | =head2 Lexically scoped warning categories |
| 298 | |
| 299 | You can now control the granularity of warnings emitted by perl at a finer |
| 300 | level using the C<use warnings> pragma. See L<warnings> and L<perllexwarn> |
| 301 | for details. |
| 302 | |
| 303 | =head2 Lvalue subroutines |
| 304 | |
| 305 | WARNING: This is an experimental feature. |
| 306 | |
| 307 | change#4081 |
| 308 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>, |
| 309 | Tuomas Lukka <lukka@fas.harvard.edu>)] |
| 310 | |
| 311 | =head2 "our" declarations |
| 312 | |
| 313 | An "our" declaration introduces a value that can be best understood |
| 314 | as a lexically scoped symbolic alias to a global variable in the |
| 315 | current package. This is mostly useful as an alternative to the |
| 316 | C<vars> pragma, but also provides the opportunity to introduce |
| 317 | typing and other attributes for such variables. See L<perlfunc/our>. |
| 318 | |
| 319 | =head2 Weak references |
| 320 | |
| 321 | WARNING: This is an experimental feature. |
| 322 | |
| 323 | change#3385, also need perlguts documentation |
| 324 | |
| 325 | [TODO - Tuomas Lukka <lukka@fas.harvard.edu>] |
| 326 | |
| 327 | =head2 Binary numbers supported |
| 328 | |
| 329 | Binary numbers are now supported as literals, in s?printf formats, and |
| 330 | C<oct()>: |
| 331 | |
| 332 | $answer = 0b101010; |
| 333 | printf "The answer is: %b\n", oct("0b101010"); |
| 334 | |
| 335 | =head2 Some arrows may be omitted in calls through references |
| 336 | |
| 337 | Perl now allows the arrow to be omitted in many constructs |
| 338 | involving subroutine calls through references. For example, |
| 339 | C<$foo[10]->('foo')> may now be written C<$foo[10]('foo')>. |
| 340 | This is rather similar to how the arrow may be omitted from |
| 341 | C<$foo[10]->{'foo'}>. Note however, that the arrow is still |
| 342 | required for C<foo(10)->('bar')>. |
| 343 | |
| 344 | =head2 syswrite() ease-of-use |
| 345 | |
| 346 | The length argument of C<syswrite()> has become optional. |
| 347 | |
| 348 | =head2 Filehandles can be autovivified |
| 349 | |
| 350 | The construct C<open(my $fh, ...)> can be used to create filehandles |
| 351 | more easily. The filehandle will be automatically closed at the end |
| 352 | of the scope of $fh, provided there are no other references to it. This |
| 353 | largely eliminates the need for typeglobs when opening filehandles |
| 354 | that must be passed around, as in the following example: |
| 355 | |
| 356 | sub myopen { |
| 357 | open my $fh, "@_" |
| 358 | or die "Can't open '@_': $!"; |
| 359 | return $fh; |
| 360 | } |
| 361 | |
| 362 | { |
| 363 | my $f = myopen("</etc/motd"); |
| 364 | print <$f>; |
| 365 | # $f implicitly closed here |
| 366 | } |
| 367 | |
| 368 | [TODO - this idiom needs more pod penetration] |
| 369 | |
| 370 | =head2 64-bit support |
| 371 | |
| 372 | All platforms that have 64-bit integers either (a) natively as longs |
| 373 | or ints (b) via special compiler flags (c) using long long are able to |
| 374 | use "quads" (64-integers) as follows: |
| 375 | |
| 376 | =over 4 |
| 377 | |
| 378 | =item * |
| 379 | |
| 380 | constants (decimal, hexadecimal, octal, binary) in the code |
| 381 | |
| 382 | =item * |
| 383 | |
| 384 | arguments to oct() and hex() |
| 385 | |
| 386 | =item * |
| 387 | |
| 388 | arguments to print(), printf() and sprintf() (flag prefixes ll, L, q) |
| 389 | |
| 390 | =item * |
| 391 | |
| 392 | printed as such |
| 393 | |
| 394 | =item * |
| 395 | |
| 396 | pack() and unpack() "q" and "Q" formats |
| 397 | |
| 398 | =item * |
| 399 | |
| 400 | in basic arithmetics: + - * / % |
| 401 | |
| 402 | =item * |
| 403 | |
| 404 | vec() (but see the below note about bit arithmetics) |
| 405 | |
| 406 | =back |
| 407 | |
| 408 | Note that unless you have the case (a) you will have to configure |
| 409 | and compile Perl using the -Duse64bits Configure flag. |
| 410 | |
| 411 | Unfortunately bit arithmetics (&, |, ^, ~, <<, >>) for numbers are not |
| 412 | 64-bit clean, they are explictly forced to be 32-bit. Bit arithmetics |
| 413 | for bit vectors (created by vec()) are not limited in their width. |
| 414 | |
| 415 | Last but not least: note that due to Perl's habit of always using |
| 416 | floating point numbers the quads are still not true integers. |
| 417 | When quads overflow their limits (0...18_446_744_073_709_551_615 unsigned, |
| 418 | -9_223_372_036_854_775_808...9_223_372_036_854_775_807 signed), they |
| 419 | are silently promoted to floating point numbers, after which they will |
| 420 | start losing precision (their lower digits). |
| 421 | |
| 422 | =head2 Large file support |
| 423 | |
| 424 | If you have filesystems that support "large files" (files larger than |
| 425 | 2 gigabytes), you may now also be able to create and access them from |
| 426 | Perl. You have to use Configure -Duselargefiles. Turning on the |
| 427 | large file support turns on also the 64-bit support, for obvious reasons. |
| 428 | |
| 429 | Note that in addition to requiring a proper file system to do large |
| 430 | files you may also need to adjust your per-process (or your |
| 431 | per-system, or per-process-group, or per-user-group) maximum filesize |
| 432 | limits before running Perl scripts that try to handle large files, |
| 433 | especially if you intend to write such files. |
| 434 | |
| 435 | Finally, in addition to your process/process group maximum filesize |
| 436 | limits, you may have quota limits on your filesystems that stop you |
| 437 | (your user id or your user group id) from using large files. |
| 438 | |
| 439 | Adjusting your process/user/group/file system/operating system limits |
| 440 | is outside the scope of Perl core language. For process limits, you |
| 441 | may try increasing the limits using your shell's limits/limit/ulimit |
| 442 | command before running Perl. The BSD::Resource extension (not |
| 443 | included with the standard Perl distribution) may also be of use, it |
| 444 | offers the getrlimit/setrlimit interface that can be used to adjust |
| 445 | process resource usage limits, including the maximum filesize limit. |
| 446 | |
| 447 | =head2 Long doubles |
| 448 | |
| 449 | In some systems you may be able to use long doubles to enhance the |
| 450 | range of precision of your double precision floating point numbers |
| 451 | (that is, Perl's numbers). Use Configure -Duselongdouble to enable |
| 452 | this support (if it is available). |
| 453 | |
| 454 | =head2 "more bits" |
| 455 | |
| 456 | You can Configure -Dusemorebits to turn on both the 64-bit support |
| 457 | and the long double support. |
| 458 | |
| 459 | =head2 Better syntax checks on parenthesized unary operators |
| 460 | |
| 461 | Expressions such as: |
| 462 | |
| 463 | print defined(&foo,&bar,&baz); |
| 464 | print uc("foo","bar","baz"); |
| 465 | undef($foo,&bar); |
| 466 | |
| 467 | used to be accidentally allowed in earlier versions, and produced |
| 468 | unpredictable behaviour. Some produced ancillary warnings |
| 469 | when used in this way; others silently did the wrong thing. |
| 470 | |
| 471 | The parenthesized forms of most unary operators that expect a single |
| 472 | argument now ensure that they are not called with more than one |
| 473 | argument, making the cases shown above syntax errors. The usual |
| 474 | behaviour of: |
| 475 | |
| 476 | print defined &foo, &bar, &baz; |
| 477 | print uc "foo", "bar", "baz"; |
| 478 | undef $foo, &bar; |
| 479 | |
| 480 | remains unchanged. See L<perlop>. |
| 481 | |
| 482 | =head2 POSIX character class syntax [: :] supported |
| 483 | |
| 484 | For example to match alphabetic characters use /[[:alpha:]]/. |
| 485 | See L<perlre> for details. |
| 486 | |
| 487 | =head2 Improved C<qw//> operator |
| 488 | |
| 489 | The C<qw//> operator is now evaluated at compile time into a true list |
| 490 | instead of being replaced with a run time call to C<split()>. This |
| 491 | removes the confusing misbehaviour of C<qw//> in scalar context, which |
| 492 | had inherited that behaviour from split(). |
| 493 | |
| 494 | Thus: |
| 495 | |
| 496 | $foo = ($bar) = qw(a b c); print "$foo|$bar\n"; |
| 497 | |
| 498 | now correctly prints "3|a", instead of "2|a". |
| 499 | |
| 500 | =head2 pack() format 'Z' supported |
| 501 | |
| 502 | The new format type 'Z' is useful for packing and unpacking null-terminated |
| 503 | strings. See L<perlfunc/"pack">. |
| 504 | |
| 505 | =head2 pack() format modifier '!' supported |
| 506 | |
| 507 | The new format type modifier '!' is useful for packing and unpacking |
| 508 | native shorts, ints, and longs. See L<perlfunc/"pack">. |
| 509 | |
| 510 | =head2 pack() and unpack() support counted strings |
| 511 | |
| 512 | The template character '/' can be used to specify a counted string |
| 513 | type to be packed or unpacked. See L<perlfunc/"pack">. |
| 514 | |
| 515 | =head2 Comments in pack() templates |
| 516 | |
| 517 | The '#' character in a template introduces a comment up to |
| 518 | end of the line. This facilitates documentation of pack() |
| 519 | templates. |
| 520 | |
| 521 | =head2 $^X variables may now have names longer than one character |
| 522 | |
| 523 | Formerly, $^X was synonymous with ${"\cX"}, but $^XY was a syntax |
| 524 | error. Now variable names that begin with a control character may be |
| 525 | arbitrarily long. However, for compatibility reasons, these variables |
| 526 | I<must> be written with explicit braces, as C<${^XY}> for example. |
| 527 | C<${^XYZ}> is synonymous with ${"\cXYZ"}. Variable names with more |
| 528 | than one control character, such as C<${^XY^Z}>, are illegal. |
| 529 | |
| 530 | The old syntax has not changed. As before, `^X' may be either a |
| 531 | literal control-X character or the two-character sequence `caret' plus |
| 532 | `X'. When braces are omitted, the variable name stops after the |
| 533 | control character. Thus C<"$^XYZ"> continues to be synonymous with |
| 534 | C<$^X . "YZ"> as before. |
| 535 | |
| 536 | As before, lexical variables may not have names beginning with control |
| 537 | characters. As before, variables whose names begin with a control |
| 538 | character are always forced to be in package `main'. All such variables |
| 539 | are reserved for future extensions, except those that begin with |
| 540 | C<^_>, which may be used by user programs and are guaranteed not to |
| 541 | acquire special meaning in any future version of Perl. |
| 542 | |
| 543 | =head2 C<use attrs> implicit in subroutine attributes |
| 544 | |
| 545 | Formerly, if you wanted to mark a subroutine as being a method call or |
| 546 | as requiring an automatic lock() when it is entered, you had to declare |
| 547 | that with a C<use attrs> pragma in the body of the subroutine. |
| 548 | That can now be accomplished with a declaration syntax, like this: |
| 549 | |
| 550 | sub mymethod : locked, method ; |
| 551 | ... |
| 552 | sub mymethod : locked, method { |
| 553 | ... |
| 554 | } |
| 555 | |
| 556 | F<AutoSplit.pm> and F<SelfLoader.pm> have been updated to keep the attributes |
| 557 | with the stubs they provide. See L<attributes>. |
| 558 | |
| 559 | =head2 Regular expression improvements |
| 560 | |
| 561 | change#2827,2373,2372,2365,1813,1800,4112,4158,4215,4301 |
| 562 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
| 563 | |
| 564 | =head2 Overloading improvements |
| 565 | |
| 566 | change#2150 |
| 567 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
| 568 | |
| 569 | =head2 open() with more than two arguments |
| 570 | |
| 571 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
| 572 | |
| 573 | =head2 Support for interpolating named characters |
| 574 | |
| 575 | change#4052 |
| 576 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
| 577 | |
| 578 | =head2 Experimental support for user-hooks in @INC |
| 579 | |
| 580 | [TODO - Ken Fox <kfox@ford.com>] |
| 581 | |
| 582 | =head2 C<require> and C<do> may be overridden |
| 583 | |
| 584 | C<require> and C<do 'file'> operations may be overridden locally |
| 585 | by importing subroutines of the same name into the current package |
| 586 | (or globally by importing them into the CORE::GLOBAL:: namespace). |
| 587 | Overriding C<require> will also affect C<use>, provided the override |
| 588 | is visible at compile-time. |
| 589 | See L<perlsub/"Overriding Built-in Functions">. |
| 590 | |
| 591 | =head2 New variable $^C reflects C<-c> switch |
| 592 | |
| 593 | C<$^C> has a boolean value that reflects whether perl is being run |
| 594 | in compile-only mode (i.e. via the C<-c> switch). Since |
| 595 | BEGIN blocks are executed under such conditions, this variable |
| 596 | enables perl code to determine whether actions that make sense |
| 597 | only during normal running are warranted. See L<perlvar>. |
| 598 | |
| 599 | =head2 Optional Y2K warnings |
| 600 | |
| 601 | If Perl is built with the cpp macro C<PERL_Y2KWARN> defined, |
| 602 | it emits optional warnings when concatenating the number 19 |
| 603 | with another number. |
| 604 | |
| 605 | This behavior must be specifically enabled when running Configure. |
| 606 | See L<INSTALL> and L<README.Y2K>. |
| 607 | |
| 608 | =head1 Significant bug fixes |
| 609 | |
| 610 | =head2 E<lt>HANDLEE<gt> on empty files |
| 611 | |
| 612 | With C<$/> set to C<undef>, slurping an empty file returns a string of |
| 613 | zero length (instead of C<undef>, as it used to) the first time the |
| 614 | HANDLE is read. Further reads yield C<undef>. |
| 615 | |
| 616 | This means that the following will append "foo" to an empty file (it used |
| 617 | to do nothing): |
| 618 | |
| 619 | perl -0777 -pi -e 's/^/foo/' empty_file |
| 620 | |
| 621 | The behaviour of: |
| 622 | |
| 623 | perl -pi -e 's/^/foo/' empty_file |
| 624 | |
| 625 | is unchanged (it continues to leave the file empty). |
| 626 | |
| 627 | =head2 C<eval '...'> improvements |
| 628 | |
| 629 | Line numbers (as reflected by caller() and most diagnostics) within |
| 630 | C<eval '...'> were often incorrect when here documents were involved. |
| 631 | This has been corrected. |
| 632 | |
| 633 | Lexical lookups for variables appearing in C<eval '...'> within |
| 634 | functions that were themselves called within an C<eval '...'> were |
| 635 | searching the wrong place for lexicals. The lexical search now |
| 636 | correctly ends at the subroutine's block boundary. |
| 637 | |
| 638 | Parsing of here documents used to be flawed when they appeared as |
| 639 | the replacement expression in C<eval 's/.../.../e'>. This has |
| 640 | been fixed. |
| 641 | |
| 642 | =head2 All compilation errors are true errors |
| 643 | |
| 644 | Some "errors" encountered at compile time were by neccessity |
| 645 | generated as warnings followed by eventual termination of the |
| 646 | program. This enabled more such errors to be reported in a |
| 647 | single run, rather than causing a hard stop at the first error |
| 648 | that was encountered. |
| 649 | |
| 650 | The mechanism for reporting such errors has been reimplemented |
| 651 | to queue compile-time errors and report them at the end of the |
| 652 | compilation as true errors rather than as warnings. This fixes |
| 653 | cases where error messages leaked through in the form of warnings |
| 654 | when code was compiled at run time using C<eval STRING>, and |
| 655 | also allows such errors to be reliably trapped using __DIE__ hooks. |
| 656 | |
| 657 | =head2 Automatic flushing of output buffers |
| 658 | |
| 659 | fork(), exec(), system(), qx//, and pipe open()s now flush buffers |
| 660 | of all files opened for output when the operation |
| 661 | was attempted. This mostly eliminates confusing |
| 662 | buffering mishaps suffered by users unaware of how Perl internally |
| 663 | handles I/O. |
| 664 | |
| 665 | =head2 Better diagnostics on meaningless filehandle operations |
| 666 | |
| 667 | Constructs such as C<open(E<lt>FHE<gt>)> and C<close(E<lt>FHE<gt>)> |
| 668 | are compile time errors. Attempting to read from filehandles that |
| 669 | were opened only for writing will now produce warnings (just as |
| 670 | writing to read-only filehandles does). |
| 671 | |
| 672 | =head2 Where possible, buffered data discarded from duped input filehandle |
| 673 | |
| 674 | C<open(NEW, "E<lt>&OLD")> now attempts to discard any data that |
| 675 | was previously read and buffered in C<OLD> before duping the handle. |
| 676 | On platforms where doing this is allowed, the next read operation |
| 677 | on C<NEW> will return the same data as the corresponding operation |
| 678 | on C<OLD>. Formerly, it would have returned the data from the start |
| 679 | of the following disk block instead. |
| 680 | |
| 681 | =head2 system(), backticks and pipe open now reflect exec() failure |
| 682 | |
| 683 | On Unix and similar platforms, system(), qx() and open(FOO, "cmd |") |
| 684 | etc., are implemented via fork() and exec(). When the underlying |
| 685 | exec() fails, earlier versions did not report the error properly, |
| 686 | since the exec() happened to be in a different process. |
| 687 | |
| 688 | The child process now communicates with the parent about the |
| 689 | error in launching the external command, which allow these |
| 690 | constructs to return with their usual error value and set $!. |
| 691 | |
| 692 | =head2 Implicitly closed filehandles are safer |
| 693 | |
| 694 | Sometimes implicitly closed filehandles (as when they are localized, |
| 695 | and Perl automatically closes them on exiting the scope) could |
| 696 | inadvertently set $? or $!. This has been corrected. |
| 697 | |
| 698 | =head2 C<(\$)> prototype and C<$foo{a}> |
| 699 | |
| 700 | An scalar reference prototype now correctly allows a hash or |
| 701 | array element in that slot. |
| 702 | |
| 703 | =head2 Pseudo-hashes work better |
| 704 | |
| 705 | Dereferencing some types of reference values in a pseudo-hash, |
| 706 | such as C<$ph->{foo}[1]>, was accidentally disallowed. This has |
| 707 | been corrected. |
| 708 | |
| 709 | When applied to a pseudo-hash element, exists() now reports whether |
| 710 | the specified value exists, not merely if the key is valid. |
| 711 | |
| 712 | =head2 C<goto &sub> and AUTOLOAD |
| 713 | |
| 714 | The C<goto &sub> construct works correctly when C<&sub> happens |
| 715 | to be autoloaded. |
| 716 | |
| 717 | =head2 C<-bareword> allowed under C<use integer> |
| 718 | |
| 719 | The autoquoting of barewords preceded by C<-> did not work |
| 720 | in prior versions when the C<integer> pragma was enabled. |
| 721 | This has been fixed. |
| 722 | |
| 723 | =head2 Boolean assignment operators are legal lvalues |
| 724 | |
| 725 | Constructs such as C<($a ||= 2) += 1> are now allowed. |
| 726 | |
| 727 | =head2 C<sort $coderef @foo> allowed |
| 728 | |
| 729 | sort() did not accept a subroutine reference as the comparison |
| 730 | function in earlier versions. This is now permitted. |
| 731 | |
| 732 | =head2 Failures in DESTROY() |
| 733 | |
| 734 | When code in a destructor threw an exception, it went unnoticed |
| 735 | in earlier versions of Perl, unless someone happened to be |
| 736 | looking in $@ just after the point the destructor happened to |
| 737 | run. Such failures are now visible as warnings when warnings are |
| 738 | enabled. |
| 739 | |
| 740 | =head2 Locale bugs fixed |
| 741 | |
| 742 | printf() and sprintf() previously did reset the numeric locale |
| 743 | back to the default "C" locale. This has been fixed. |
| 744 | |
| 745 | Numbers formatted according to the local numeric locale |
| 746 | (such as using a decimal comma instead of a decimal dot) caused |
| 747 | "isn't numeric" warnings, even while the operations accessing |
| 748 | those numbers produced correct results. The warnings are gone. |
| 749 | |
| 750 | =head2 Memory leaks |
| 751 | |
| 752 | The C<eval 'return sub {...}'> construct could sometimes leak |
| 753 | memory. This has been fixed. |
| 754 | |
| 755 | Operations that aren't filehandle constructors used to leak memory |
| 756 | when used on invalid filehandles. This has been fixed. |
| 757 | |
| 758 | Constructs that modified C<@_> could fail to deallocate values |
| 759 | in C<@_> and thus leak memory. This has been corrected. |
| 760 | |
| 761 | =head2 Spurious subroutine stubs after failed subroutine calls |
| 762 | |
| 763 | Perl could sometimes create empty subroutine stubs when a |
| 764 | subroutine was not found in the package. Such cases stopped |
| 765 | later method lookups from progressing into base packages. |
| 766 | This has been corrected. |
| 767 | |
| 768 | =head2 Consistent numeric conversions |
| 769 | |
| 770 | change#3378,3318 |
| 771 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
| 772 | |
| 773 | =head2 Taint failures under C<-U> |
| 774 | |
| 775 | When running in unsafe mode, taint violations could sometimes |
| 776 | cause silent failures. This has been fixed. |
| 777 | |
| 778 | =head2 END blocks and the C<-c> switch |
| 779 | |
| 780 | Prior versions used to run BEGIN B<and> END blocks when Perl was |
| 781 | run in compile-only mode. Since this is typically not the expected |
| 782 | behavior, END blocks are not executed anymore when the C<-c> switch |
| 783 | is used. |
| 784 | |
| 785 | Note that something resembling the previous behavior can still be |
| 786 | obtained by putting C<BEGIN { $^C = 0; exit; } at the very end of |
| 787 | the top level source file. |
| 788 | |
| 789 | =head2 Potential to leak DATA filehandles |
| 790 | |
| 791 | Using the C<__DATA__> token creates an implicit filehandle to |
| 792 | the file that contains the token. It is the program's |
| 793 | responsibility to close it when it is done reading from it. |
| 794 | |
| 795 | This caveat is now better explained in the documentation. |
| 796 | See L<perldata>. |
| 797 | |
| 798 | =head2 Diagnostics follow STDERR |
| 799 | |
| 800 | Diagnostic output now goes to whichever file the C<STDERR> handle |
| 801 | is pointing at, instead of always going to the underlying C runtime |
| 802 | library's C<stderr>. |
| 803 | |
| 804 | =head2 Other fixes for better diagnostics |
| 805 | |
| 806 | Line numbers are suppressed no more (under most likely circumstances) |
| 807 | during the global destruction phase. |
| 808 | |
| 809 | Diagnostics emitted from code running in threads other than the main |
| 810 | thread are now accompanied by the thread ID. |
| 811 | |
| 812 | Embedded null characters in diagnostics now actually show up. They |
| 813 | used to truncate the message in prior versions. |
| 814 | |
| 815 | $foo::a and $foo::b are now exempt from "possible typo" warnings only |
| 816 | if sort() is encountered in package foo. |
| 817 | |
| 818 | Unrecognized alphabetic escapes encountered when parsing quoting |
| 819 | constructs now generate a warning, since they may take on new |
| 820 | semantics in later versions of Perl. |
| 821 | |
| 822 | =head1 Performance enhancements |
| 823 | |
| 824 | =head2 Simple sort() using { $a <=> $b } and the like are optimized |
| 825 | |
| 826 | Many common sort() operations using a simple inlined block are now |
| 827 | optimized for faster performance. |
| 828 | |
| 829 | =head2 Optimized assignments to lexical variables |
| 830 | |
| 831 | Certain operations in the RHS of assignment statements have been |
| 832 | optimized to directly set the lexical variable on the LHS, |
| 833 | eliminating redundant copying overheads. |
| 834 | |
| 835 | =head2 Method lookups optimized |
| 836 | |
| 837 | [TODO - Chip Salzenberg <chip@perlsupport.com>] |
| 838 | |
| 839 | =head2 Faster mechanism to invoke XSUBs |
| 840 | |
| 841 | change#4044,4125 |
| 842 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
| 843 | |
| 844 | =head2 Perl_malloc() improvements |
| 845 | |
| 846 | change#4237 |
| 847 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
| 848 | |
| 849 | =head2 Faster subroutine calls |
| 850 | |
| 851 | Minor changes in how subroutine calls are handled internally |
| 852 | provide marginal improvements in performance. |
| 853 | |
| 854 | =head1 Platform specific changes |
| 855 | |
| 856 | =head2 Additional supported platforms |
| 857 | |
| 858 | =over 4 |
| 859 | |
| 860 | =item * |
| 861 | |
| 862 | VM/ESA is now supported. |
| 863 | |
| 864 | =item * |
| 865 | |
| 866 | Siemens BS2000 is now supported under the POSIX Shell. |
| 867 | |
| 868 | =item * |
| 869 | |
| 870 | The Mach CThreads (NEXTSTEP, OPENSTEP) are now supported by the Thread |
| 871 | extension. |
| 872 | |
| 873 | =item * |
| 874 | |
| 875 | GNU/Hurd is now supported. |
| 876 | |
| 877 | =item * |
| 878 | |
| 879 | Rhapsody is now supported. |
| 880 | |
| 881 | =item * |
| 882 | |
| 883 | EPOC is is now supported (on Psion 5). |
| 884 | |
| 885 | =back |
| 886 | |
| 887 | =head2 DOS |
| 888 | |
| 889 | [TODO - Laszlo Molnar <laszlo.molnar@eth.ericsson.se>] |
| 890 | |
| 891 | =head2 OS/2 |
| 892 | |
| 893 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
| 894 | |
| 895 | =head2 VMS |
| 896 | |
| 897 | [TODO - Charles Bailey <bailey@newman.upenn.edu>] |
| 898 | |
| 899 | =head2 Win32 |
| 900 | |
| 901 | Site library searches failed to look for ".../site/5.XXX/lib" |
| 902 | if ".../site/5.XXXYY/lib" wasn't found. This has been corrected. |
| 903 | |
| 904 | When given a pathname that consists only of a drivename, such |
| 905 | as C<A:>, opendir() and stat() now use the current working |
| 906 | directory for the drive rather than the drive root. |
| 907 | |
| 908 | The builtin XSUB functions in the Win32:: namespace are |
| 909 | documented. See L<Win32>. |
| 910 | |
| 911 | $^X now contains the full path name of the running executable. |
| 912 | |
| 913 | A Win32::GetLongPathName() function is provided to complement |
| 914 | Win32::GetFullPathName() and Win32::GetShortPathName(). See L<Win32>. |
| 915 | |
| 916 | POSIX::uname() is supported. |
| 917 | |
| 918 | system(1,...) now returns true process IDs rather than process |
| 919 | handles. kill() accepts any real process id, rather than strictly |
| 920 | return values from system(1,...). |
| 921 | |
| 922 | The C<Shell> module is supported. |
| 923 | |
| 924 | [TODO - GSAR] |
| 925 | |
| 926 | =head1 New tests |
| 927 | |
| 928 | =over 4 |
| 929 | |
| 930 | =item lib/attrs |
| 931 | |
| 932 | Compatibility tests for C<sub : attrs> vs the older C<use attrs>. |
| 933 | |
| 934 | =item lib/io_const |
| 935 | |
| 936 | IO constants (SEEK_*, _IO*). |
| 937 | |
| 938 | =item lib/io_dir |
| 939 | |
| 940 | Directory-related IO methods (new, read, close, rewind, tied delete). |
| 941 | |
| 942 | =item lib/io_multihomed |
| 943 | |
| 944 | INET sockets with multi-homed hosts. |
| 945 | |
| 946 | =item lib/io_poll |
| 947 | |
| 948 | IO poll(). |
| 949 | |
| 950 | =item lib/io_unix |
| 951 | |
| 952 | UNIX sockets. |
| 953 | |
| 954 | =item op/attrs |
| 955 | |
| 956 | Regression tests for C<my ($x,@y,%z) : attrs> and <sub : attrs>. |
| 957 | |
| 958 | =item op/filetest |
| 959 | |
| 960 | File test operators. |
| 961 | |
| 962 | =item op/lex_assign |
| 963 | |
| 964 | Verify operations that access pad objects (lexicals and temporaries). |
| 965 | |
| 966 | =back |
| 967 | |
| 968 | =head1 Modules and Pragmata |
| 969 | |
| 970 | =head2 Modules |
| 971 | |
| 972 | =over 4 |
| 973 | |
| 974 | =item attributes |
| 975 | |
| 976 | While used internally by Perl as a pragma, this module also |
| 977 | provides a way to fetch subroutine and variable attributes. |
| 978 | See L<attributes>. |
| 979 | |
| 980 | =item B |
| 981 | |
| 982 | [TODO - Vishal Bhatia <vishal@gol.com>, |
| 983 | Nick Ing-Simmons <nick@ni-s.u-net.com>] |
| 984 | |
| 985 | =item ByteLoader |
| 986 | |
| 987 | The ByteLoader is a dedicated extension to generate and run |
| 988 | Perl bytecode. See L<ByteLoader>. |
| 989 | |
| 990 | =item B |
| 991 | |
| 992 | The Perl Compiler suite has been extensively reworked for this |
| 993 | release. |
| 994 | |
| 995 | =item constant |
| 996 | |
| 997 | References can now be used. See L<constant>. |
| 998 | |
| 999 | =item charnames |
| 1000 | |
| 1001 | change#4052 |
| 1002 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
| 1003 | |
| 1004 | =item Data::Dumper |
| 1005 | |
| 1006 | A C<Maxdepth> setting can be specified to avoid venturing |
| 1007 | too deeply into data structures that may be very deep. |
| 1008 | See L<Data::Dumper>. |
| 1009 | |
| 1010 | Dumping C<qr//> objects works correctly. |
| 1011 | |
| 1012 | =item DB |
| 1013 | |
| 1014 | C<DB> is an experimental module that exposes a clean abstraction |
| 1015 | to Perl's debugging API. |
| 1016 | |
| 1017 | =item DB_File |
| 1018 | |
| 1019 | [TODO - Paul Marquess <paul.marquess@bt.com>] |
| 1020 | |
| 1021 | =item Devel::DProf |
| 1022 | |
| 1023 | Devel::DProf, a Perl source code profiler has been added. See L<DProf>. |
| 1024 | |
| 1025 | =item Dumpvalue |
| 1026 | |
| 1027 | Added Dumpvalue module provides screen dumps of Perl data. |
| 1028 | |
| 1029 | =item Benchmark |
| 1030 | |
| 1031 | You can now run tests for I<n> seconds instead of guessing the right |
| 1032 | number of tests to run: e.g. timethese(-5, ...) will run each |
| 1033 | code for at least 5 CPU seconds. Zero as the "number of repetitions" |
| 1034 | means "for at least 3 CPU seconds". The output format has also |
| 1035 | changed. For example: |
| 1036 | |
| 1037 | use Benchmark;$x=3;timethese(-5,{a=>sub{$x*$x},b=>sub{$x**2}}) |
| 1038 | |
| 1039 | will now output something like this: |
| 1040 | |
| 1041 | Benchmark: running a, b, each for at least 5 CPU seconds... |
| 1042 | a: 5 wallclock secs ( 5.77 usr + 0.00 sys = 5.77 CPU) @ 200551.91/s (n=1156516) |
| 1043 | b: 4 wallclock secs ( 5.00 usr + 0.02 sys = 5.02 CPU) @ 159605.18/s (n=800686) |
| 1044 | |
| 1045 | New features: "each for at least N CPU seconds...", "wallclock secs", |
| 1046 | and the "@ operations/CPU second (n=operations)". |
| 1047 | |
| 1048 | change#4265,4266,4292 |
| 1049 | [TODO - Barrie Slaymaker <barries@slaysys.com>] |
| 1050 | |
| 1051 | =item Devel::Peek |
| 1052 | |
| 1053 | The Devel::Peek module provides access to the internal representation |
| 1054 | of Perl variables and data. It is a data debugging tool for the XS programmer. |
| 1055 | |
| 1056 | =item ExtUtils::MakeMaker |
| 1057 | |
| 1058 | change#4135, also needs docs in module pod |
| 1059 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
| 1060 | |
| 1061 | =item Fcntl |
| 1062 | |
| 1063 | More Fcntl constants added: F_SETLK64, F_SETLKW64, O_LARGEFILE for |
| 1064 | large (more than 4G) file access (64-bit support is not yet |
| 1065 | working, though, so no need to get overly excited), Free/Net/OpenBSD |
| 1066 | locking behaviour flags F_FLOCK, F_POSIX, Linux F_SHLCK, and |
| 1067 | O_ACCMODE: the mask of O_RDONLY, O_WRONLY, and O_RDWR. |
| 1068 | |
| 1069 | =item File::Compare |
| 1070 | |
| 1071 | A compare_text() function has been added, which allows custom |
| 1072 | comparison functions. See L<File::Compare>. |
| 1073 | |
| 1074 | =item File::Find |
| 1075 | |
| 1076 | File::Find now works correctly when the wanted() function is either |
| 1077 | autoloaded or is a symbolic reference. |
| 1078 | |
| 1079 | A bug that caused File::Find to lose track of the working directory |
| 1080 | when pruning top-level directories has been fixed. |
| 1081 | |
| 1082 | =item File::Spec |
| 1083 | |
| 1084 | New methods have been added to the File::Spec module: devnull() returns |
| 1085 | the name of the null device (/dev/null on Unix) and tmpdir() the name of |
| 1086 | the temp directory (normally /tmp on Unix). There are now also methods |
| 1087 | to convert between absolute and relative filenames: abs2rel() and |
| 1088 | rel2abs(). For compatibility with operating systems that specify volume |
| 1089 | names in file paths, the splitpath(), splitdir(), and catdir() methods |
| 1090 | have been added. |
| 1091 | |
| 1092 | =item File::Spec::Functions |
| 1093 | |
| 1094 | The new File::Spec::Functions modules provides a function interface |
| 1095 | to the File::Spec module. Allows shorthand |
| 1096 | |
| 1097 | $fullname = catfile($dir1, $dir2, $file); |
| 1098 | |
| 1099 | instead of |
| 1100 | |
| 1101 | $fullname = File::Spec->catfile($dir1, $dir2, $file); |
| 1102 | |
| 1103 | =item Getopt::Long |
| 1104 | |
| 1105 | [TODO - Johan Vromans <jvromans@squirrel.nl>] |
| 1106 | |
| 1107 | =item IO |
| 1108 | |
| 1109 | write() and syswrite() will now accept a single-argument |
| 1110 | form of the call, for consistency with Perl's syswrite(). |
| 1111 | |
| 1112 | You can now create a TCP-based IO::Socket::INET without forcing |
| 1113 | a connect attempt. This allows you to configure its options |
| 1114 | (like making it non-blocking) and then call connect() manually. |
| 1115 | |
| 1116 | A bug that prevented the IO::Socket::protocol() accessor |
| 1117 | from ever returning the correct value has been corrected. |
| 1118 | |
| 1119 | =item JPL |
| 1120 | |
| 1121 | Java Perl Lingo is now distributed with Perl. See jpl/README |
| 1122 | for more information. |
| 1123 | |
| 1124 | =item Math::BigInt |
| 1125 | |
| 1126 | The logical operations C<E<lt>E<lt>>, C<E<gt>E<gt>>, C<&>, C<|>, |
| 1127 | and C<~> are now supported on bigints. |
| 1128 | |
| 1129 | =item Math::Complex |
| 1130 | |
| 1131 | The accessor methods Re, Im, arg, abs, rho, and theta can now also |
| 1132 | act as mutators (accessor $z->Re(), mutator $z->Re(3)). |
| 1133 | |
| 1134 | =item Math::Trig |
| 1135 | |
| 1136 | A little bit of radial trigonometry (cylindrical and spherical), |
| 1137 | radial coordinate conversions, and the great circle distance were added. |
| 1138 | |
| 1139 | =item Pod::Parser |
| 1140 | |
| 1141 | [TODO - Brad Appleton <bradapp@enteract.com>] |
| 1142 | |
| 1143 | =item Pod::Text and Pod::Man |
| 1144 | |
| 1145 | [TODO - Russ Allbery <rra@stanford.edu>] |
| 1146 | |
| 1147 | =item SDBM_File |
| 1148 | |
| 1149 | An EXISTS method has been added to this module (and sdbm_exists() has |
| 1150 | been added to the underlying sdbm library), so one can now call exists |
| 1151 | on an SDBM_File tied hash and get the correct result, rather than a |
| 1152 | runtime error. |
| 1153 | |
| 1154 | A bug that may have caused data loss when more than one disk block |
| 1155 | happens to be read from the database in a single FETCH() has been |
| 1156 | fixed. |
| 1157 | |
| 1158 | =item Time::Local |
| 1159 | |
| 1160 | The timelocal() and timegm() functions used to silently return bogus |
| 1161 | results when the date exceeded the machine's integer range. They |
| 1162 | now consistently croak() if the date falls in an unsupported range. |
| 1163 | |
| 1164 | =item Win32 |
| 1165 | |
| 1166 | The error return value in list context has been changed for all functions |
| 1167 | that return a list of values. Previously these functions returned a list |
| 1168 | with a single element C<undef> if an error occurred. Now these functions |
| 1169 | return the empty list in these situations. This applies to the following |
| 1170 | functions: |
| 1171 | |
| 1172 | Win32::FsType |
| 1173 | Win32::GetOSVersion |
| 1174 | |
| 1175 | The remaining functions are unchanged and continue to return C<undef> on |
| 1176 | error even in list context. |
| 1177 | |
| 1178 | The Win32::SetLastError(ERROR) function has been added as a complement |
| 1179 | to the Win32::GetLastError() function. |
| 1180 | |
| 1181 | The new Win32::GetFullPathName(FILENAME) returns the full absolute |
| 1182 | pathname for FILENAME in scalar context. In list context it returns |
| 1183 | a two-element list containing the fully qualified directory name and |
| 1184 | the filename. |
| 1185 | |
| 1186 | =item DBM Filters |
| 1187 | |
| 1188 | A new feature called "DBM Filters" has been added to all the |
| 1189 | DBM modules--DB_File, GDBM_File, NDBM_File, ODBM_File, and SDBM_File. |
| 1190 | DBM Filters add four new methods to each DBM module: |
| 1191 | |
| 1192 | filter_store_key |
| 1193 | filter_store_value |
| 1194 | filter_fetch_key |
| 1195 | filter_fetch_value |
| 1196 | |
| 1197 | These can be used to filter key-value pairs before the pairs are |
| 1198 | written to the database or just after they are read from the database. |
| 1199 | See L<perldbmfilter> for further information. |
| 1200 | |
| 1201 | =back |
| 1202 | |
| 1203 | =head2 Pragmata |
| 1204 | |
| 1205 | C<use attrs> is now obsolescent, and is only provided for |
| 1206 | backward-compatibility. It's been replaced by the C<sub : attributes> |
| 1207 | syntax. See L<perlsub/"Subroutine Attributes"> and L<attributes>. |
| 1208 | |
| 1209 | C<use utf8> to enable UTF-8 and Unicode support. |
| 1210 | |
| 1211 | C<use caller 'encoding'> allows modules to inherit pragmatic attributes |
| 1212 | from the caller's context. C<encoding> is currently the only supported |
| 1213 | attribute. |
| 1214 | |
| 1215 | Lexical warnings pragma, C<use warnings;>, to control optional warnings. |
| 1216 | See L<perllexwarn>. |
| 1217 | |
| 1218 | C<use filetest> to control the behaviour of filetests (C<-r> C<-w> |
| 1219 | ...). Currently only one subpragma implemented, "use filetest |
| 1220 | 'access';", that uses access(2) or equivalent to check permissions |
| 1221 | instead of using stat(2) as usual. This matters in filesystems |
| 1222 | where there are ACLs (access control lists): the stat(2) might lie, |
| 1223 | but access(2) knows better. |
| 1224 | |
| 1225 | =head1 Utility Changes |
| 1226 | |
| 1227 | =head2 h2ph |
| 1228 | |
| 1229 | [TODO - Kurt Starsinic <kstar@chapin.edu>] |
| 1230 | |
| 1231 | =head2 perlcc |
| 1232 | |
| 1233 | C<perlcc> now supports the C and Bytecode backends. By default, |
| 1234 | it generates output from the simple C backend rather than the |
| 1235 | optimized C backend. |
| 1236 | |
| 1237 | Support for non-Unix platforms has been improved. |
| 1238 | |
| 1239 | =head2 h2xs |
| 1240 | |
| 1241 | change#4232 |
| 1242 | [TODO - Ilya Zakharevich <ilya@math.ohio-state.edu>] |
| 1243 | |
| 1244 | =head1 Documentation Changes |
| 1245 | |
| 1246 | =over 4 |
| 1247 | |
| 1248 | =item perlopentut.pod |
| 1249 | |
| 1250 | A tutorial on using open() effectively. |
| 1251 | |
| 1252 | =item perlreftut.pod |
| 1253 | |
| 1254 | A tutorial that introduces the essentials of references. |
| 1255 | |
| 1256 | =item perltootc.pod |
| 1257 | |
| 1258 | A tutorial on managing class data for object modules. |
| 1259 | |
| 1260 | =item perlcompile.pod |
| 1261 | |
| 1262 | An introduction to using the Perl Compiler suite. |
| 1263 | |
| 1264 | =back |
| 1265 | |
| 1266 | =head1 New Diagnostics |
| 1267 | |
| 1268 | =over 4 |
| 1269 | |
| 1270 | =item "my sub" not yet implemented |
| 1271 | |
| 1272 | (F) Lexically scoped subroutines are not yet implemented. Don't try that |
| 1273 | yet. |
| 1274 | |
| 1275 | =item '!' allowed only after types %s |
| 1276 | |
| 1277 | (F) The '!' is allowed in pack() and unpack() only after certain types. |
| 1278 | See L<perlfunc/pack>. |
| 1279 | |
| 1280 | =item / cannot take a count |
| 1281 | |
| 1282 | (F) You had an unpack template indicating a counted-length string, |
| 1283 | but you have also specified an explicit size for the string. |
| 1284 | See L<perlfunc/pack>. |
| 1285 | |
| 1286 | =item / must be followed by a, A or Z |
| 1287 | |
| 1288 | (F) You had an unpack template indicating a counted-length string, |
| 1289 | which must be followed by one of the letters a, A or Z |
| 1290 | to indicate what sort of string is to be unpacked. |
| 1291 | See L<perlfunc/pack>. |
| 1292 | |
| 1293 | =item / must be followed by a*, A* or Z* |
| 1294 | |
| 1295 | (F) You had an pack template indicating a counted-length string, |
| 1296 | Currently the only things that can have their length counted are a*, A* or Z*. |
| 1297 | See L<perlfunc/pack>. |
| 1298 | |
| 1299 | =item / must follow a numeric type |
| 1300 | |
| 1301 | (F) You had an unpack template that contained a '#', |
| 1302 | but this did not follow some numeric unpack specification. |
| 1303 | See L<perlfunc/pack>. |
| 1304 | |
| 1305 | =item Repeat count in pack overflows |
| 1306 | |
| 1307 | (F) You can't specify a repeat count so large that it overflows |
| 1308 | your signed integers. See L<perlfunc/pack>. |
| 1309 | |
| 1310 | =item Repeat count in unpack overflows |
| 1311 | |
| 1312 | (F) You can't specify a repeat count so large that it overflows |
| 1313 | your signed integers. See L<perlfunc/unpack>. |
| 1314 | |
| 1315 | =item /%s/: Unrecognized escape \\%c passed through |
| 1316 | |
| 1317 | (W) You used a backslash-character combination which is not recognized |
| 1318 | by Perl. This combination appears in an interpolated variable or a |
| 1319 | C<'>-delimited regular expression. |
| 1320 | |
| 1321 | =item /%s/ should probably be written as "%s" |
| 1322 | |
| 1323 | (W) You have used a pattern where Perl expected to find a string, |
| 1324 | like in the first argument to C<join>. Perl will treat the true |
| 1325 | or false result of matching the pattern against $_ as the string, |
| 1326 | which is probably not what you had in mind. |
| 1327 | |
| 1328 | =item %s() called too early to check prototype |
| 1329 | |
| 1330 | (W) You've called a function that has a prototype before the parser saw a |
| 1331 | definition or declaration for it, and Perl could not check that the call |
| 1332 | conforms to the prototype. You need to either add an early prototype |
| 1333 | declaration for the subroutine in question, or move the subroutine |
| 1334 | definition ahead of the call to get proper prototype checking. Alternatively, |
| 1335 | if you are certain that you're calling the function correctly, you may put |
| 1336 | an ampersand before the name to avoid the warning. See L<perlsub>. |
| 1337 | |
| 1338 | =item %s package attribute may clash with future reserved word: %s |
| 1339 | |
| 1340 | (W) A lowercase attribute name was used that had a package-specific handler. |
| 1341 | That name might have a meaning to Perl itself some day, even though it |
| 1342 | doesn't yet. Perhaps you should use a mixed-case attribute name, instead. |
| 1343 | See L<attributes>. |
| 1344 | |
| 1345 | =item (in cleanup) %s |
| 1346 | |
| 1347 | (W) This prefix usually indicates that a DESTROY() method raised |
| 1348 | the indicated exception. Since destructors are usually called by |
| 1349 | the system at arbitrary points during execution, and often a vast |
| 1350 | number of times, the warning is issued only once for any number |
| 1351 | of failures that would otherwise result in the same message being |
| 1352 | repeated. |
| 1353 | |
| 1354 | Failure of user callbacks dispatched using the C<G_KEEPERR> flag |
| 1355 | could also result in this warning. See L<perlcall/G_KEEPERR>. |
| 1356 | |
| 1357 | =item <> should be quotes |
| 1358 | |
| 1359 | (F) You wrote C<require E<lt>fileE<gt>> when you should have written |
| 1360 | C<require 'file'>. |
| 1361 | |
| 1362 | =item Attempt to join self |
| 1363 | |
| 1364 | (F) You tried to join a thread from within itself, which is an |
| 1365 | impossible task. You may be joining the wrong thread, or you may |
| 1366 | need to move the join() to some other thread. |
| 1367 | |
| 1368 | =item Bad evalled substitution pattern |
| 1369 | |
| 1370 | (F) You've used the /e switch to evaluate the replacement for a |
| 1371 | substitution, but perl found a syntax error in the code to evaluate, |
| 1372 | most likely an unexpected right brace '}'. |
| 1373 | |
| 1374 | =item Bad realloc() ignored |
| 1375 | |
| 1376 | (S) An internal routine called realloc() on something that had never been |
| 1377 | malloc()ed in the first place. Mandatory, but can be disabled by |
| 1378 | setting environment variable C<PERL_BADFREE> to 1. |
| 1379 | |
| 1380 | =item Binary number > 0b11111111111111111111111111111111 non-portable |
| 1381 | |
| 1382 | (W) The binary number you specified is larger than 2**32-1 |
| 1383 | (4294967295) and therefore non-portable between systems. See |
| 1384 | L<perlport> for more on portability concerns. |
| 1385 | |
| 1386 | =item Bit vector size > 32 non-portable |
| 1387 | |
| 1388 | (W) Using bit vector sizes larger than 32 is non-portable. |
| 1389 | |
| 1390 | =item Buffer overflow in prime_env_iter: %s |
| 1391 | |
| 1392 | (W) A warning peculiar to VMS. While Perl was preparing to iterate over |
| 1393 | %ENV, it encountered a logical name or symbol definition which was too long, |
| 1394 | so it was truncated to the string shown. |
| 1395 | |
| 1396 | =item Can't check filesystem of script "%s" |
| 1397 | |
| 1398 | (P) For some reason you can't check the filesystem of the script for nosuid. |
| 1399 | |
| 1400 | =item Can't modify non-lvalue subroutine call |
| 1401 | |
| 1402 | (F) Subroutines used in lvalue context should be marked as such, see |
| 1403 | L<perlsub/"Lvalue subroutines">. |
| 1404 | |
| 1405 | =item Can't read CRTL environ |
| 1406 | |
| 1407 | (S) A warning peculiar to VMS. Perl tried to read an element of %ENV |
| 1408 | from the CRTL's internal environment array and discovered the array was |
| 1409 | missing. You need to figure out where your CRTL misplaced its environ |
| 1410 | or define F<PERL_ENV_TABLES> (see L<perlvms>) so that environ is not searched. |
| 1411 | |
| 1412 | =item Can't remove %s: %s, skipping file |
| 1413 | |
| 1414 | (S) You requested an inplace edit without creating a backup file. Perl |
| 1415 | was unable to remove the original file to replace it with the modified |
| 1416 | file. The file was left unmodified. |
| 1417 | |
| 1418 | =item Can't return %s from lvalue subroutine |
| 1419 | |
| 1420 | (F) Perl detected an attempt to return illegal lvalues (such |
| 1421 | as temporary or readonly values) from a subroutine used as an lvalue. |
| 1422 | This is not allowed. |
| 1423 | |
| 1424 | =item Can't weaken a nonreference |
| 1425 | |
| 1426 | (F) You attempted to weaken something that was not a reference. Only |
| 1427 | references can be weakened. |
| 1428 | |
| 1429 | =item Character class [:%s:] unknown |
| 1430 | |
| 1431 | (F) The class in the character class [: :] syntax is unknown. |
| 1432 | |
| 1433 | =item Character class syntax [%s] belongs inside character classes |
| 1434 | |
| 1435 | (W) The character class constructs [: :], [= =], and [. .] go |
| 1436 | I<inside> character classes, the [] are part of the construct, |
| 1437 | for example: /[012[:alpha:]345]/. Note that the last two constructs |
| 1438 | are not currently implemented, they are placeholders for future extensions. |
| 1439 | |
| 1440 | =item Constant is not %s reference |
| 1441 | |
| 1442 | (F) A constant value (perhaps declared using the C<use constant> pragma) |
| 1443 | is being dereferenced, but it amounts to the wrong type of reference. The |
| 1444 | message indicates the type of reference that was expected. This usually |
| 1445 | indicates a syntax error in dereferencing the constant value. |
| 1446 | See L<perlsub/"Constant Functions"> and L<constant>. |
| 1447 | |
| 1448 | =item constant(%s): %%^H is not localized |
| 1449 | |
| 1450 | (F) When setting compile-time-lexicalized hash %^H one should set the |
| 1451 | corresponding bit of $^H as well. |
| 1452 | |
| 1453 | =item constant(%s): %s |
| 1454 | |
| 1455 | (F) Compile-time-substitutions (such as overloaded constants and |
| 1456 | character names) were not correctly set up. |
| 1457 | |
| 1458 | =item defined(@array) is deprecated |
| 1459 | |
| 1460 | (D) defined() is not usually useful on arrays because it checks for an |
| 1461 | undefined I<scalar> value. If you want to see if the array is empty, |
| 1462 | just use C<if (@array) { # not empty }> for example. |
| 1463 | |
| 1464 | =item defined(%hash) is deprecated |
| 1465 | |
| 1466 | (D) defined() is not usually useful on hashes because it checks for an |
| 1467 | undefined I<scalar> value. If you want to see if the hash is empty, |
| 1468 | just use C<if (%hash) { # not empty }> for example. |
| 1469 | |
| 1470 | =item Did not produce a valid header |
| 1471 | |
| 1472 | See Server error. |
| 1473 | |
| 1474 | =item Document contains no data |
| 1475 | |
| 1476 | See Server error. |
| 1477 | |
| 1478 | =item entering effective %s failed |
| 1479 | |
| 1480 | (F) While under the C<use filetest> pragma, switching the real and |
| 1481 | effective uids or gids failed. |
| 1482 | |
| 1483 | =item Filehandle %s opened only for output |
| 1484 | |
| 1485 | (W) You tried to read from a filehandle opened only for writing. If you |
| 1486 | intended it to be a read-write filehandle, you needed to open it with |
| 1487 | "+E<lt>" or "+E<gt>" or "+E<gt>E<gt>" instead of with "E<lt>" or nothing. If |
| 1488 | you intended only to read from the file, use "E<lt>". See |
| 1489 | L<perlfunc/open>. |
| 1490 | |
| 1491 | =item Hexadecimal number > 0xffffffff non-portable |
| 1492 | |
| 1493 | (W) The hexadecimal number you specified is larger than 2**32-1 |
| 1494 | (4294967295) and therefore non-portable between systems. See |
| 1495 | L<perlport> for more on portability concerns. |
| 1496 | |
| 1497 | =item Ill-formed CRTL environ value "%s" |
| 1498 | |
| 1499 | (W) A warning peculiar to VMS. Perl tried to read the CRTL's internal |
| 1500 | environ array, and encountered an element without the C<=> delimiter |
| 1501 | used to spearate keys from values. The element is ignored. |
| 1502 | |
| 1503 | =item Ill-formed message in prime_env_iter: |%s| |
| 1504 | |
| 1505 | (W) A warning peculiar to VMS. Perl tried to read a logical name |
| 1506 | or CLI symbol definition when preparing to iterate over %ENV, and |
| 1507 | didn't see the expected delimiter between key and value, so the |
| 1508 | line was ignored. |
| 1509 | |
| 1510 | =item Illegal binary digit %s |
| 1511 | |
| 1512 | (F) You used a digit other than 0 and 1 in a binary number. |
| 1513 | |
| 1514 | =item Illegal binary digit %s ignored |
| 1515 | |
| 1516 | (W) You may have tried to use a digit other than 0 or 1 in a binary number. |
| 1517 | Interpretation of the binary number stopped before the offending digit. |
| 1518 | |
| 1519 | =item Illegal number of bits in vec |
| 1520 | |
| 1521 | (F) The number of bits in vec() (the third argument) must be a power of |
| 1522 | two from 1 to 32 (or 64, if your platform supports that). |
| 1523 | |
| 1524 | =item Integer overflow in %s number |
| 1525 | |
| 1526 | (W) The hexadecimal, octal or binary number you have specified either |
| 1527 | as a literal in your code or as a scalar is too big for your |
| 1528 | architecture, and has been converted to a floating point number. On a |
| 1529 | 32-bit architecture the largest hexadecimal, octal or binary number |
| 1530 | representable without overflow is 0xFFFFFFFF, 037777777777, or |
| 1531 | 0b11111111111111111111111111111111 respectively. Note that Perl |
| 1532 | transparently promotes all numbers to a floating point representation |
| 1533 | internally--subject to loss of precision errors in subsequent |
| 1534 | operations. |
| 1535 | |
| 1536 | =item Invalid %s attribute: %s |
| 1537 | |
| 1538 | The indicated attribute for a subroutine or variable was not recognized |
| 1539 | by Perl or by a user-supplied handler. See L<attributes>. |
| 1540 | |
| 1541 | =item Invalid %s attributes: %s |
| 1542 | |
| 1543 | The indicated attributes for a subroutine or variable were not recognized |
| 1544 | by Perl or by a user-supplied handler. See L<attributes>. |
| 1545 | |
| 1546 | =item Invalid separator character %s in attribute list |
| 1547 | |
| 1548 | (F) Something other than a comma or whitespace was seen between the |
| 1549 | elements of an attribute list. If the previous attribute |
| 1550 | had a parenthesised parameter list, perhaps that list was terminated |
| 1551 | too soon. See L<attributes>. |
| 1552 | |
| 1553 | =item Invalid separator character %s in subroutine attribute list |
| 1554 | |
| 1555 | (F) Something other than a comma or whitespace was seen between the |
| 1556 | elements of a subroutine attribute list. If the previous attribute |
| 1557 | had a parenthesised parameter list, perhaps that list was terminated |
| 1558 | too soon. |
| 1559 | |
| 1560 | =item leaving effective %s failed |
| 1561 | |
| 1562 | (F) While under the C<use filetest> pragma, switching the real and |
| 1563 | effective uids or gids failed. |
| 1564 | |
| 1565 | =item Lvalue subs returning %s not implemented yet |
| 1566 | |
| 1567 | (F) Due to limitations in the current implementation, array and hash |
| 1568 | values cannot be returned in subroutines used in lvalue context. |
| 1569 | See L<perlsub/"Lvalue subroutines">. |
| 1570 | |
| 1571 | =item Method %s not permitted |
| 1572 | |
| 1573 | See Server error. |
| 1574 | |
| 1575 | =item Missing %sbrace%s on \N{} |
| 1576 | |
| 1577 | (F) Wrong syntax of character name literal C<\N{charname}> within |
| 1578 | double-quotish context. |
| 1579 | |
| 1580 | =item Missing command in piped open |
| 1581 | |
| 1582 | (W) You used the C<open(FH, "| command")> or C<open(FH, "command |")> |
| 1583 | construction, but the command was missing or blank. |
| 1584 | |
| 1585 | =item Missing name in "my sub" |
| 1586 | |
| 1587 | (F) The reserved syntax for lexically scoped subroutines requires that they |
| 1588 | have a name with which they can be found. |
| 1589 | |
| 1590 | =item no UTC offset information; assuming local time is UTC |
| 1591 | |
| 1592 | (S) A warning peculiar to VMS. Perl was unable to find the local |
| 1593 | timezone offset, so it's assuming that local system time is equivalent |
| 1594 | to UTC. If it's not, define the logical name F<SYS$TIMEZONE_DIFFERENTIAL> |
| 1595 | to translate to the number of seconds which need to be added to UTC to |
| 1596 | get local time. |
| 1597 | |
| 1598 | =item Octal number > 037777777777 non-portable |
| 1599 | |
| 1600 | (W) The octal number you specified is larger than 2**32-1 (4294967295) |
| 1601 | and therefore non-portable between systems. See L<perlport> for more |
| 1602 | on portability concerns. |
| 1603 | |
| 1604 | See also L<perlport> for writing portable code. |
| 1605 | |
| 1606 | =item panic: del_backref |
| 1607 | |
| 1608 | (P) Failed an internal consistency check while trying to reset a weak |
| 1609 | reference. |
| 1610 | |
| 1611 | =item panic: kid popen errno read |
| 1612 | |
| 1613 | (F) forked child returned an incomprehensible message about its errno. |
| 1614 | |
| 1615 | =item panic: magic_killbackrefs |
| 1616 | |
| 1617 | (P) Failed an internal consistency check while trying to reset all weak |
| 1618 | references to an object. |
| 1619 | |
| 1620 | =item Possible Y2K bug: %s |
| 1621 | |
| 1622 | (W) You are concatenating the number 19 with another number, which |
| 1623 | could be a potential Year 2000 problem. |
| 1624 | |
| 1625 | =item Premature end of script headers |
| 1626 | |
| 1627 | See Server error. |
| 1628 | |
| 1629 | =item realloc() of freed memory ignored |
| 1630 | |
| 1631 | (S) An internal routine called realloc() on something that had already |
| 1632 | been freed. |
| 1633 | |
| 1634 | =item Reference is already weak |
| 1635 | |
| 1636 | (W) You have attempted to weaken a reference that is already weak. |
| 1637 | Doing so has no effect. |
| 1638 | |
| 1639 | =item setpgrp can't take arguments |
| 1640 | |
| 1641 | (F) Your system has the setpgrp() from BSD 4.2, which takes no arguments, |
| 1642 | unlike POSIX setpgid(), which takes a process ID and process group ID. |
| 1643 | |
| 1644 | =item Strange *+?{} on zero-length expression |
| 1645 | |
| 1646 | (W) You applied a regular expression quantifier in a place where it |
| 1647 | makes no sense, such as on a zero-width assertion. |
| 1648 | Try putting the quantifier inside the assertion instead. For example, |
| 1649 | the way to match "abc" provided that it is followed by three |
| 1650 | repetitions of "xyz" is C</abc(?=(?:xyz){3})/>, not C</abc(?=xyz){3}/>. |
| 1651 | |
| 1652 | =item switching effective %s is not implemented |
| 1653 | |
| 1654 | (F) While under the C<use filetest> pragma, we cannot switch the |
| 1655 | real and effective uids or gids. |
| 1656 | |
| 1657 | =item This Perl can't reset CRTL eviron elements (%s) |
| 1658 | |
| 1659 | =item This Perl can't set CRTL environ elements (%s=%s) |
| 1660 | |
| 1661 | (W) Warnings peculiar to VMS. You tried to change or delete an element |
| 1662 | of the CRTL's internal environ array, but your copy of Perl wasn't |
| 1663 | built with a CRTL that contained the setenv() function. You'll need to |
| 1664 | rebuild Perl with a CRTL that does, or redefine F<PERL_ENV_TABLES> (see |
| 1665 | L<perlvms>) so that the environ array isn't the target of the change to |
| 1666 | %ENV which produced the warning. |
| 1667 | |
| 1668 | =item Unknown open() mode '%s' |
| 1669 | |
| 1670 | (F) The second argument of 3-arguments open is not one from the list |
| 1671 | of C<L<lt>>, C<L<gt>>, C<E<gt>E<gt>>, C<+L<lt>>, C<+L<gt>>, |
| 1672 | C<+E<gt>E<gt>>, C<-|>, C<|-> of possible open() modes. |
| 1673 | |
| 1674 | =item Unknown process %x sent message to prime_env_iter: %s |
| 1675 | |
| 1676 | (P) An error peculiar to VMS. Perl was reading values for %ENV before |
| 1677 | iterating over it, and someone else stuck a message in the stream of |
| 1678 | data Perl expected. Someone's very confused, or perhaps trying to |
| 1679 | subvert Perl's population of %ENV for nefarious purposes. |
| 1680 | |
| 1681 | =item Unrecognized escape \\%c passed through |
| 1682 | |
| 1683 | (W) You used a backslash-character combination which is not recognized |
| 1684 | by Perl. |
| 1685 | |
| 1686 | =item Unterminated attribute parameter in attribute list |
| 1687 | |
| 1688 | (F) The lexer saw an opening (left) parenthesis character while parsing an |
| 1689 | attribute list, but the matching closing (right) parenthesis |
| 1690 | character was not found. You may need to add (or remove) a backslash |
| 1691 | character to get your parentheses to balance. See L<attributes>. |
| 1692 | |
| 1693 | =item Unterminated attribute list |
| 1694 | |
| 1695 | (F) The lexer found something other than a simple identifier at the start |
| 1696 | of an attribute, and it wasn't a semicolon or the start of a |
| 1697 | block. Perhaps you terminated the parameter list of the previous attribute |
| 1698 | too soon. See L<attributes>. |
| 1699 | |
| 1700 | =item Unterminated attribute parameter in subroutine attribute list |
| 1701 | |
| 1702 | (F) The lexer saw an opening (left) parenthesis character while parsing a |
| 1703 | subroutine attribute list, but the matching closing (right) parenthesis |
| 1704 | character was not found. You may need to add (or remove) a backslash |
| 1705 | character to get your parentheses to balance. |
| 1706 | |
| 1707 | =item Unterminated subroutine attribute list |
| 1708 | |
| 1709 | (F) The lexer found something other than a simple identifier at the start |
| 1710 | of a subroutine attribute, and it wasn't a semicolon or the start of a |
| 1711 | block. Perhaps you terminated the parameter list of the previous attribute |
| 1712 | too soon. |
| 1713 | |
| 1714 | =item Value of CLI symbol "%s" too long |
| 1715 | |
| 1716 | (W) A warning peculiar to VMS. Perl tried to read the value of an %ENV |
| 1717 | element from a CLI symbol table, and found a resultant string longer |
| 1718 | than 1024 characters. The return value has been truncated to 1024 |
| 1719 | characters. |
| 1720 | |
| 1721 | =item Version number must be a constant number |
| 1722 | |
| 1723 | (P) The attempt to translate a C<use Module n.n LIST> statement into |
| 1724 | its equivalent C<BEGIN> block found an internal inconsistency with |
| 1725 | the version number. |
| 1726 | |
| 1727 | =back |
| 1728 | |
| 1729 | =head1 Obsolete Diagnostics |
| 1730 | |
| 1731 | =over 4 |
| 1732 | |
| 1733 | =item Character class syntax [: :] is reserved for future extensions |
| 1734 | |
| 1735 | (W) Within regular expression character classes ([]) the syntax beginning |
| 1736 | with "[:" and ending with ":]" is reserved for future extensions. |
| 1737 | If you need to represent those character sequences inside a regular |
| 1738 | expression character class, just quote the square brackets with the |
| 1739 | backslash: "\[:" and ":\]". |
| 1740 | |
| 1741 | =item Ill-formed logical name |%s| in prime_env_iter |
| 1742 | |
| 1743 | (W) A warning peculiar to VMS. A logical name was encountered when preparing |
| 1744 | to iterate over %ENV which violates the syntactic rules governing logical |
| 1745 | names. Because it cannot be translated normally, it is skipped, and will not |
| 1746 | appear in %ENV. This may be a benign occurrence, as some software packages |
| 1747 | might directly modify logical name tables and introduce nonstandard names, |
| 1748 | or it may indicate that a logical name table has been corrupted. |
| 1749 | |
| 1750 | =item regexp too big |
| 1751 | |
| 1752 | (F) The current implementation of regular expressions uses shorts as |
| 1753 | address offsets within a string. Unfortunately this means that if |
| 1754 | the regular expression compiles to longer than 32767, it'll blow up. |
| 1755 | Usually when you want a regular expression this big, there is a better |
| 1756 | way to do it with multiple statements. See L<perlre>. |
| 1757 | |
| 1758 | =item Use of "$$<digit>" to mean "${$}<digit>" is deprecated |
| 1759 | |
| 1760 | (D) Perl versions before 5.004 misinterpreted any type marker followed |
| 1761 | by "$" and a digit. For example, "$$0" was incorrectly taken to mean |
| 1762 | "${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004. |
| 1763 | |
| 1764 | However, the developers of Perl 5.004 could not fix this bug completely, |
| 1765 | because at least two widely-used modules depend on the old meaning of |
| 1766 | "$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the |
| 1767 | old (broken) way inside strings; but it generates this message as a |
| 1768 | warning. And in Perl 5.005, this special treatment will cease. |
| 1769 | |
| 1770 | =back |
| 1771 | |
| 1772 | =head1 BUGS |
| 1773 | |
| 1774 | If you find what you think is a bug, you might check the headers of |
| 1775 | articles recently posted to the comp.lang.perl.misc newsgroup. |
| 1776 | There may also be information at http://www.perl.com/perl/, the Perl |
| 1777 | Home Page. |
| 1778 | |
| 1779 | If you believe you have an unreported bug, please run the B<perlbug> |
| 1780 | program included with your release. Make sure to trim your bug down |
| 1781 | to a tiny but sufficient test case. Your bug report, along with the |
| 1782 | output of C<perl -V>, will be sent off to perlbug@perl.com to be |
| 1783 | analysed by the Perl porting team. |
| 1784 | |
| 1785 | =head1 SEE ALSO |
| 1786 | |
| 1787 | The F<Changes> file for exhaustive details on what changed. |
| 1788 | |
| 1789 | The F<INSTALL> file for how to build Perl. |
| 1790 | |
| 1791 | The F<README> file for general stuff. |
| 1792 | |
| 1793 | The F<Artistic> and F<Copying> files for copyright information. |
| 1794 | |
| 1795 | =head1 HISTORY |
| 1796 | |
| 1797 | Written by Gurusamy Sarathy <F<gsar@activestate.com>>, with many |
| 1798 | contributions from The Perl Porters. |
| 1799 | |
| 1800 | Send omissions or corrections to <F<perlbug@perl.com>>. |
| 1801 | |
| 1802 | =cut |