| 1 | =head1 NAME |
| 2 | |
| 3 | perl5004delta - what's new for perl5.004 |
| 4 | |
| 5 | =head1 DESCRIPTION |
| 6 | |
| 7 | This document describes differences between the 5.003 release (as |
| 8 | documented in I<Programming Perl>, second edition--the Camel Book) and |
| 9 | this one. |
| 10 | |
| 11 | =head1 Supported Environments |
| 12 | |
| 13 | Perl5.004 builds out of the box on Unix, Plan 9, LynxOS, VMS, OS/2, |
| 14 | QNX, AmigaOS, and Windows NT. Perl runs on Windows 95 as well, but it |
| 15 | cannot be built there, for lack of a reasonable command interpreter. |
| 16 | |
| 17 | =head1 Core Changes |
| 18 | |
| 19 | Most importantly, many bugs were fixed, including several security |
| 20 | problems. See the F<Changes> file in the distribution for details. |
| 21 | |
| 22 | =head2 List assignment to %ENV works |
| 23 | |
| 24 | C<%ENV = ()> and C<%ENV = @list> now work as expected (except on VMS |
| 25 | where it generates a fatal error). |
| 26 | |
| 27 | =head2 Change to "Can't locate Foo.pm in @INC" error |
| 28 | |
| 29 | The error "Can't locate Foo.pm in @INC" now lists the contents of @INC |
| 30 | for easier debugging. |
| 31 | |
| 32 | =head2 Compilation option: Binary compatibility with 5.003 |
| 33 | |
| 34 | There is a new Configure question that asks if you want to maintain |
| 35 | binary compatibility with Perl 5.003. If you choose binary |
| 36 | compatibility, you do not have to recompile your extensions, but you |
| 37 | might have symbol conflicts if you embed Perl in another application, |
| 38 | just as in the 5.003 release. By default, binary compatibility |
| 39 | is preserved at the expense of symbol table pollution. |
| 40 | |
| 41 | =head2 $PERL5OPT environment variable |
| 42 | |
| 43 | You may now put Perl options in the $PERL5OPT environment variable. |
| 44 | Unless Perl is running with taint checks, it will interpret this |
| 45 | variable as if its contents had appeared on a "#!perl" line at the |
| 46 | beginning of your script, except that hyphens are optional. PERL5OPT |
| 47 | may only be used to set the following switches: B<-[DIMUdmw]>. |
| 48 | |
| 49 | =head2 Limitations on B<-M>, B<-m>, and B<-T> options |
| 50 | |
| 51 | The C<-M> and C<-m> options are no longer allowed on the C<#!> line of |
| 52 | a script. If a script needs a module, it should invoke it with the |
| 53 | C<use> pragma. |
| 54 | |
| 55 | The B<-T> option is also forbidden on the C<#!> line of a script, |
| 56 | unless it was present on the Perl command line. Due to the way C<#!> |
| 57 | works, this usually means that B<-T> must be in the first argument. |
| 58 | Thus: |
| 59 | |
| 60 | #!/usr/bin/perl -T -w |
| 61 | |
| 62 | will probably work for an executable script invoked as C<scriptname>, |
| 63 | while: |
| 64 | |
| 65 | #!/usr/bin/perl -w -T |
| 66 | |
| 67 | will probably fail under the same conditions. (Non-Unix systems will |
| 68 | probably not follow this rule.) But C<perl scriptname> is guaranteed |
| 69 | to fail, since then there is no chance of B<-T> being found on the |
| 70 | command line before it is found on the C<#!> line. |
| 71 | |
| 72 | =head2 More precise warnings |
| 73 | |
| 74 | If you removed the B<-w> option from your Perl 5.003 scripts because it |
| 75 | made Perl too verbose, we recommend that you try putting it back when |
| 76 | you upgrade to Perl 5.004. Each new perl version tends to remove some |
| 77 | undesirable warnings, while adding new warnings that may catch bugs in |
| 78 | your scripts. |
| 79 | |
| 80 | =head2 Deprecated: Inherited C<AUTOLOAD> for non-methods |
| 81 | |
| 82 | Before Perl 5.004, C<AUTOLOAD> functions were looked up as methods |
| 83 | (using the C<@ISA> hierarchy), even when the function to be autoloaded |
| 84 | was called as a plain function (e.g. C<Foo::bar()>), not a method |
| 85 | (e.g. C<< Foo->bar() >> or C<< $obj->bar() >>). |
| 86 | |
| 87 | Perl 5.005 will use method lookup only for methods' C<AUTOLOAD>s. |
| 88 | However, there is a significant base of existing code that may be using |
| 89 | the old behavior. So, as an interim step, Perl 5.004 issues an optional |
| 90 | warning when a non-method uses an inherited C<AUTOLOAD>. |
| 91 | |
| 92 | The simple rule is: Inheritance will not work when autoloading |
| 93 | non-methods. The simple fix for old code is: In any module that used to |
| 94 | depend on inheriting C<AUTOLOAD> for non-methods from a base class named |
| 95 | C<BaseClass>, execute C<*AUTOLOAD = \&BaseClass::AUTOLOAD> during startup. |
| 96 | |
| 97 | =head2 Previously deprecated %OVERLOAD is no longer usable |
| 98 | |
| 99 | Using %OVERLOAD to define overloading was deprecated in 5.003. |
| 100 | Overloading is now defined using the overload pragma. %OVERLOAD is |
| 101 | still used internally but should not be used by Perl scripts. See |
| 102 | L<overload> for more details. |
| 103 | |
| 104 | =head2 Subroutine arguments created only when they're modified |
| 105 | |
| 106 | In Perl 5.004, nonexistent array and hash elements used as subroutine |
| 107 | parameters are brought into existence only if they are actually |
| 108 | assigned to (via C<@_>). |
| 109 | |
| 110 | Earlier versions of Perl vary in their handling of such arguments. |
| 111 | Perl versions 5.002 and 5.003 always brought them into existence. |
| 112 | Perl versions 5.000 and 5.001 brought them into existence only if |
| 113 | they were not the first argument (which was almost certainly a bug). |
| 114 | Earlier versions of Perl never brought them into existence. |
| 115 | |
| 116 | For example, given this code: |
| 117 | |
| 118 | undef @a; undef %a; |
| 119 | sub show { print $_[0] }; |
| 120 | sub change { $_[0]++ }; |
| 121 | show($a[2]); |
| 122 | change($a{b}); |
| 123 | |
| 124 | After this code executes in Perl 5.004, $a{b} exists but $a[2] does |
| 125 | not. In Perl 5.002 and 5.003, both $a{b} and $a[2] would have existed |
| 126 | (but $a[2]'s value would have been undefined). |
| 127 | |
| 128 | =head2 Group vector changeable with C<$)> |
| 129 | |
| 130 | The C<$)> special variable has always (well, in Perl 5, at least) |
| 131 | reflected not only the current effective group, but also the group list |
| 132 | as returned by the C<getgroups()> C function (if there is one). |
| 133 | However, until this release, there has not been a way to call the |
| 134 | C<setgroups()> C function from Perl. |
| 135 | |
| 136 | In Perl 5.004, assigning to C<$)> is exactly symmetrical with examining |
| 137 | it: The first number in its string value is used as the effective gid; |
| 138 | if there are any numbers after the first one, they are passed to the |
| 139 | C<setgroups()> C function (if there is one). |
| 140 | |
| 141 | =head2 Fixed parsing of $$<digit>, &$<digit>, etc. |
| 142 | |
| 143 | Perl versions before 5.004 misinterpreted any type marker followed by |
| 144 | "$" and a digit. For example, "$$0" was incorrectly taken to mean |
| 145 | "${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004. |
| 146 | |
| 147 | However, the developers of Perl 5.004 could not fix this bug completely, |
| 148 | because at least two widely-used modules depend on the old meaning of |
| 149 | "$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the |
| 150 | old (broken) way inside strings; but it generates this message as a |
| 151 | warning. And in Perl 5.005, this special treatment will cease. |
| 152 | |
| 153 | =head2 Fixed localization of $<digit>, $&, etc. |
| 154 | |
| 155 | Perl versions before 5.004 did not always properly localize the |
| 156 | regex-related special variables. Perl 5.004 does localize them, as |
| 157 | the documentation has always said it should. This may result in $1, |
| 158 | $2, etc. no longer being set where existing programs use them. |
| 159 | |
| 160 | =head2 No resetting of $. on implicit close |
| 161 | |
| 162 | The documentation for Perl 5.0 has always stated that C<$.> is I<not> |
| 163 | reset when an already-open file handle is reopened with no intervening |
| 164 | call to C<close>. Due to a bug, perl versions 5.000 through 5.003 |
| 165 | I<did> reset C<$.> under that circumstance; Perl 5.004 does not. |
| 166 | |
| 167 | =head2 C<wantarray> may return undef |
| 168 | |
| 169 | The C<wantarray> operator returns true if a subroutine is expected to |
| 170 | return a list, and false otherwise. In Perl 5.004, C<wantarray> can |
| 171 | also return the undefined value if a subroutine's return value will |
| 172 | not be used at all, which allows subroutines to avoid a time-consuming |
| 173 | calculation of a return value if it isn't going to be used. |
| 174 | |
| 175 | =head2 C<eval EXPR> determines value of EXPR in scalar context |
| 176 | |
| 177 | Perl (version 5) used to determine the value of EXPR inconsistently, |
| 178 | sometimes incorrectly using the surrounding context for the determination. |
| 179 | Now, the value of EXPR (before being parsed by eval) is always determined in |
| 180 | a scalar context. Once parsed, it is executed as before, by providing |
| 181 | the context that the scope surrounding the eval provided. This change |
| 182 | makes the behavior Perl4 compatible, besides fixing bugs resulting from |
| 183 | the inconsistent behavior. This program: |
| 184 | |
| 185 | @a = qw(time now is time); |
| 186 | print eval @a; |
| 187 | print '|', scalar eval @a; |
| 188 | |
| 189 | used to print something like "timenowis881399109|4", but now (and in perl4) |
| 190 | prints "4|4". |
| 191 | |
| 192 | =head2 Changes to tainting checks |
| 193 | |
| 194 | A bug in previous versions may have failed to detect some insecure |
| 195 | conditions when taint checks are turned on. (Taint checks are used |
| 196 | in setuid or setgid scripts, or when explicitly turned on with the |
| 197 | C<-T> invocation option.) Although it's unlikely, this may cause a |
| 198 | previously-working script to now fail, which should be construed |
| 199 | as a blessing since that indicates a potentially-serious security |
| 200 | hole was just plugged. |
| 201 | |
| 202 | The new restrictions when tainting include: |
| 203 | |
| 204 | =over 4 |
| 205 | |
| 206 | =item No glob() or <*> |
| 207 | |
| 208 | These operators may spawn the C shell (csh), which cannot be made |
| 209 | safe. This restriction will be lifted in a future version of Perl |
| 210 | when globbing is implemented without the use of an external program. |
| 211 | |
| 212 | =item No spawning if tainted $CDPATH, $ENV, $BASH_ENV |
| 213 | |
| 214 | These environment variables may alter the behavior of spawned programs |
| 215 | (especially shells) in ways that subvert security. So now they are |
| 216 | treated as dangerous, in the manner of $IFS and $PATH. |
| 217 | |
| 218 | =item No spawning if tainted $TERM doesn't look like a terminal name |
| 219 | |
| 220 | Some termcap libraries do unsafe things with $TERM. However, it would be |
| 221 | unnecessarily harsh to treat all $TERM values as unsafe, since only shell |
| 222 | metacharacters can cause trouble in $TERM. So a tainted $TERM is |
| 223 | considered to be safe if it contains only alphanumerics, underscores, |
| 224 | dashes, and colons, and unsafe if it contains other characters (including |
| 225 | whitespace). |
| 226 | |
| 227 | =back |
| 228 | |
| 229 | =head2 New Opcode module and revised Safe module |
| 230 | |
| 231 | A new Opcode module supports the creation, manipulation and |
| 232 | application of opcode masks. The revised Safe module has a new API |
| 233 | and is implemented using the new Opcode module. Please read the new |
| 234 | Opcode and Safe documentation. |
| 235 | |
| 236 | =head2 Embedding improvements |
| 237 | |
| 238 | In older versions of Perl it was not possible to create more than one |
| 239 | Perl interpreter instance inside a single process without leaking like a |
| 240 | sieve and/or crashing. The bugs that caused this behavior have all been |
| 241 | fixed. However, you still must take care when embedding Perl in a C |
| 242 | program. See the updated perlembed manpage for tips on how to manage |
| 243 | your interpreters. |
| 244 | |
| 245 | =head2 Internal change: FileHandle class based on IO::* classes |
| 246 | |
| 247 | File handles are now stored internally as type IO::Handle. The |
| 248 | FileHandle module is still supported for backwards compatibility, but |
| 249 | it is now merely a front end to the IO::* modules, specifically |
| 250 | IO::Handle, IO::Seekable, and IO::File. We suggest, but do not |
| 251 | require, that you use the IO::* modules in new code. |
| 252 | |
| 253 | In harmony with this change, C<*GLOB{FILEHANDLE}> is now just a |
| 254 | backward-compatible synonym for C<*GLOB{IO}>. |
| 255 | |
| 256 | =head2 Internal change: PerlIO abstraction interface |
| 257 | |
| 258 | It is now possible to build Perl with AT&T's sfio IO package |
| 259 | instead of stdio. See L<perlapio> for more details, and |
| 260 | the F<INSTALL> file for how to use it. |
| 261 | |
| 262 | =head2 New and changed syntax |
| 263 | |
| 264 | =over 4 |
| 265 | |
| 266 | =item $coderef->(PARAMS) |
| 267 | |
| 268 | A subroutine reference may now be suffixed with an arrow and a |
| 269 | (possibly empty) parameter list. This syntax denotes a call of the |
| 270 | referenced subroutine, with the given parameters (if any). |
| 271 | |
| 272 | This new syntax follows the pattern of S<C<< $hashref->{FOO} >>> and |
| 273 | S<C<< $aryref->[$foo] >>>: You may now write S<C<&$subref($foo)>> as |
| 274 | S<C<< $subref->($foo) >>>. All these arrow terms may be chained; |
| 275 | thus, S<C<< &{$table->{FOO}}($bar) >>> may now be written |
| 276 | S<C<< $table->{FOO}->($bar) >>>. |
| 277 | |
| 278 | =back |
| 279 | |
| 280 | =head2 New and changed builtin constants |
| 281 | |
| 282 | =over 4 |
| 283 | |
| 284 | =item __PACKAGE__ |
| 285 | |
| 286 | The current package name at compile time, or the undefined value if |
| 287 | there is no current package (due to a C<package;> directive). Like |
| 288 | C<__FILE__> and C<__LINE__>, C<__PACKAGE__> does I<not> interpolate |
| 289 | into strings. |
| 290 | |
| 291 | =back |
| 292 | |
| 293 | =head2 New and changed builtin variables |
| 294 | |
| 295 | =over 4 |
| 296 | |
| 297 | =item $^E |
| 298 | |
| 299 | Extended error message on some platforms. (Also known as |
| 300 | $EXTENDED_OS_ERROR if you C<use English>). |
| 301 | |
| 302 | =item $^H |
| 303 | |
| 304 | The current set of syntax checks enabled by C<use strict>. See the |
| 305 | documentation of C<strict> for more details. Not actually new, but |
| 306 | newly documented. |
| 307 | Because it is intended for internal use by Perl core components, |
| 308 | there is no C<use English> long name for this variable. |
| 309 | |
| 310 | =item $^M |
| 311 | |
| 312 | By default, running out of memory it is not trappable. However, if |
| 313 | compiled for this, Perl may use the contents of C<$^M> as an emergency |
| 314 | pool after die()ing with this message. Suppose that your Perl were |
| 315 | compiled with -DPERL_EMERGENCY_SBRK and used Perl's malloc. Then |
| 316 | |
| 317 | $^M = 'a' x (1<<16); |
| 318 | |
| 319 | would allocate a 64K buffer for use when in emergency. |
| 320 | See the F<INSTALL> file for information on how to enable this option. |
| 321 | As a disincentive to casual use of this advanced feature, |
| 322 | there is no C<use English> long name for this variable. |
| 323 | |
| 324 | =back |
| 325 | |
| 326 | =head2 New and changed builtin functions |
| 327 | |
| 328 | =over 4 |
| 329 | |
| 330 | =item delete on slices |
| 331 | |
| 332 | This now works. (e.g. C<delete @ENV{'PATH', 'MANPATH'}>) |
| 333 | |
| 334 | =item flock |
| 335 | |
| 336 | is now supported on more platforms, prefers fcntl to lockf when |
| 337 | emulating, and always flushes before (un)locking. |
| 338 | |
| 339 | =item printf and sprintf |
| 340 | |
| 341 | Perl now implements these functions itself; it doesn't use the C |
| 342 | library function sprintf() any more, except for floating-point |
| 343 | numbers, and even then only known flags are allowed. As a result, it |
| 344 | is now possible to know which conversions and flags will work, and |
| 345 | what they will do. |
| 346 | |
| 347 | The new conversions in Perl's sprintf() are: |
| 348 | |
| 349 | %i a synonym for %d |
| 350 | %p a pointer (the address of the Perl value, in hexadecimal) |
| 351 | %n special: *stores* the number of characters output so far |
| 352 | into the next variable in the parameter list |
| 353 | |
| 354 | The new flags that go between the C<%> and the conversion are: |
| 355 | |
| 356 | # prefix octal with "0", hex with "0x" |
| 357 | h interpret integer as C type "short" or "unsigned short" |
| 358 | V interpret integer as Perl's standard integer type |
| 359 | |
| 360 | Also, where a number would appear in the flags, an asterisk ("*") may |
| 361 | be used instead, in which case Perl uses the next item in the |
| 362 | parameter list as the given number (that is, as the field width or |
| 363 | precision). If a field width obtained through "*" is negative, it has |
| 364 | the same effect as the '-' flag: left-justification. |
| 365 | |
| 366 | See L<perlfunc/sprintf> for a complete list of conversion and flags. |
| 367 | |
| 368 | =item keys as an lvalue |
| 369 | |
| 370 | As an lvalue, C<keys> allows you to increase the number of hash buckets |
| 371 | allocated for the given hash. This can gain you a measure of efficiency if |
| 372 | you know the hash is going to get big. (This is similar to pre-extending |
| 373 | an array by assigning a larger number to $#array.) If you say |
| 374 | |
| 375 | keys %hash = 200; |
| 376 | |
| 377 | then C<%hash> will have at least 200 buckets allocated for it. These |
| 378 | buckets will be retained even if you do C<%hash = ()>; use C<undef |
| 379 | %hash> if you want to free the storage while C<%hash> is still in scope. |
| 380 | You can't shrink the number of buckets allocated for the hash using |
| 381 | C<keys> in this way (but you needn't worry about doing this by accident, |
| 382 | as trying has no effect). |
| 383 | |
| 384 | =item my() in Control Structures |
| 385 | |
| 386 | You can now use my() (with or without the parentheses) in the control |
| 387 | expressions of control structures such as: |
| 388 | |
| 389 | while (defined(my $line = <>)) { |
| 390 | $line = lc $line; |
| 391 | } continue { |
| 392 | print $line; |
| 393 | } |
| 394 | |
| 395 | if ((my $answer = <STDIN>) =~ /^y(es)?$/i) { |
| 396 | user_agrees(); |
| 397 | } elsif ($answer =~ /^n(o)?$/i) { |
| 398 | user_disagrees(); |
| 399 | } else { |
| 400 | chomp $answer; |
| 401 | die "`$answer' is neither `yes' nor `no'"; |
| 402 | } |
| 403 | |
| 404 | Also, you can declare a foreach loop control variable as lexical by |
| 405 | preceding it with the word "my". For example, in: |
| 406 | |
| 407 | foreach my $i (1, 2, 3) { |
| 408 | some_function(); |
| 409 | } |
| 410 | |
| 411 | $i is a lexical variable, and the scope of $i extends to the end of |
| 412 | the loop, but not beyond it. |
| 413 | |
| 414 | Note that you still cannot use my() on global punctuation variables |
| 415 | such as $_ and the like. |
| 416 | |
| 417 | =item pack() and unpack() |
| 418 | |
| 419 | A new format 'w' represents a BER compressed integer (as defined in |
| 420 | ASN.1). Its format is a sequence of one or more bytes, each of which |
| 421 | provides seven bits of the total value, with the most significant |
| 422 | first. Bit eight of each byte is set, except for the last byte, in |
| 423 | which bit eight is clear. |
| 424 | |
| 425 | If 'p' or 'P' are given undef as values, they now generate a NULL |
| 426 | pointer. |
| 427 | |
| 428 | Both pack() and unpack() now fail when their templates contain invalid |
| 429 | types. (Invalid types used to be ignored.) |
| 430 | |
| 431 | =item sysseek() |
| 432 | |
| 433 | The new sysseek() operator is a variant of seek() that sets and gets the |
| 434 | file's system read/write position, using the lseek(2) system call. It is |
| 435 | the only reliable way to seek before using sysread() or syswrite(). Its |
| 436 | return value is the new position, or the undefined value on failure. |
| 437 | |
| 438 | =item use VERSION |
| 439 | |
| 440 | If the first argument to C<use> is a number, it is treated as a version |
| 441 | number instead of a module name. If the version of the Perl interpreter |
| 442 | is less than VERSION, then an error message is printed and Perl exits |
| 443 | immediately. Because C<use> occurs at compile time, this check happens |
| 444 | immediately during the compilation process, unlike C<require VERSION>, |
| 445 | which waits until runtime for the check. This is often useful if you |
| 446 | need to check the current Perl version before C<use>ing library modules |
| 447 | which have changed in incompatible ways from older versions of Perl. |
| 448 | (We try not to do this more than we have to.) |
| 449 | |
| 450 | =item use Module VERSION LIST |
| 451 | |
| 452 | If the VERSION argument is present between Module and LIST, then the |
| 453 | C<use> will call the VERSION method in class Module with the given |
| 454 | version as an argument. The default VERSION method, inherited from |
| 455 | the UNIVERSAL class, croaks if the given version is larger than the |
| 456 | value of the variable $Module::VERSION. (Note that there is not a |
| 457 | comma after VERSION!) |
| 458 | |
| 459 | This version-checking mechanism is similar to the one currently used |
| 460 | in the Exporter module, but it is faster and can be used with modules |
| 461 | that don't use the Exporter. It is the recommended method for new |
| 462 | code. |
| 463 | |
| 464 | =item prototype(FUNCTION) |
| 465 | |
| 466 | Returns the prototype of a function as a string (or C<undef> if the |
| 467 | function has no prototype). FUNCTION is a reference to or the name of the |
| 468 | function whose prototype you want to retrieve. |
| 469 | (Not actually new; just never documented before.) |
| 470 | |
| 471 | =item srand |
| 472 | |
| 473 | The default seed for C<srand>, which used to be C<time>, has been changed. |
| 474 | Now it's a heady mix of difficult-to-predict system-dependent values, |
| 475 | which should be sufficient for most everyday purposes. |
| 476 | |
| 477 | Previous to version 5.004, calling C<rand> without first calling C<srand> |
| 478 | would yield the same sequence of random numbers on most or all machines. |
| 479 | Now, when perl sees that you're calling C<rand> and haven't yet called |
| 480 | C<srand>, it calls C<srand> with the default seed. You should still call |
| 481 | C<srand> manually if your code might ever be run on a pre-5.004 system, |
| 482 | of course, or if you want a seed other than the default. |
| 483 | |
| 484 | =item $_ as Default |
| 485 | |
| 486 | Functions documented in the Camel to default to $_ now in |
| 487 | fact do, and all those that do are so documented in L<perlfunc>. |
| 488 | |
| 489 | =item C<m//gc> does not reset search position on failure |
| 490 | |
| 491 | The C<m//g> match iteration construct has always reset its target |
| 492 | string's search position (which is visible through the C<pos> operator) |
| 493 | when a match fails; as a result, the next C<m//g> match after a failure |
| 494 | starts again at the beginning of the string. With Perl 5.004, this |
| 495 | reset may be disabled by adding the "c" (for "continue") modifier, |
| 496 | i.e. C<m//gc>. This feature, in conjunction with the C<\G> zero-width |
| 497 | assertion, makes it possible to chain matches together. See L<perlop> |
| 498 | and L<perlre>. |
| 499 | |
| 500 | =item C<m//x> ignores whitespace before ?*+{} |
| 501 | |
| 502 | The C<m//x> construct has always been intended to ignore all unescaped |
| 503 | whitespace. However, before Perl 5.004, whitespace had the effect of |
| 504 | escaping repeat modifiers like "*" or "?"; for example, C</a *b/x> was |
| 505 | (mis)interpreted as C</a\*b/x>. This bug has been fixed in 5.004. |
| 506 | |
| 507 | =item nested C<sub{}> closures work now |
| 508 | |
| 509 | Prior to the 5.004 release, nested anonymous functions didn't work |
| 510 | right. They do now. |
| 511 | |
| 512 | =item formats work right on changing lexicals |
| 513 | |
| 514 | Just like anonymous functions that contain lexical variables |
| 515 | that change (like a lexical index variable for a C<foreach> loop), |
| 516 | formats now work properly. For example, this silently failed |
| 517 | before (printed only zeros), but is fine now: |
| 518 | |
| 519 | my $i; |
| 520 | foreach $i ( 1 .. 10 ) { |
| 521 | write; |
| 522 | } |
| 523 | format = |
| 524 | my i is @# |
| 525 | $i |
| 526 | . |
| 527 | |
| 528 | However, it still fails (without a warning) if the foreach is within a |
| 529 | subroutine: |
| 530 | |
| 531 | my $i; |
| 532 | sub foo { |
| 533 | foreach $i ( 1 .. 10 ) { |
| 534 | write; |
| 535 | } |
| 536 | } |
| 537 | foo; |
| 538 | format = |
| 539 | my i is @# |
| 540 | $i |
| 541 | . |
| 542 | |
| 543 | =back |
| 544 | |
| 545 | =head2 New builtin methods |
| 546 | |
| 547 | The C<UNIVERSAL> package automatically contains the following methods that |
| 548 | are inherited by all other classes: |
| 549 | |
| 550 | =over 4 |
| 551 | |
| 552 | =item isa(CLASS) |
| 553 | |
| 554 | C<isa> returns I<true> if its object is blessed into a subclass of C<CLASS> |
| 555 | |
| 556 | C<isa> is also exportable and can be called as a sub with two arguments. This |
| 557 | allows the ability to check what a reference points to. Example: |
| 558 | |
| 559 | use UNIVERSAL qw(isa); |
| 560 | |
| 561 | if(isa($ref, 'ARRAY')) { |
| 562 | ... |
| 563 | } |
| 564 | |
| 565 | =item can(METHOD) |
| 566 | |
| 567 | C<can> checks to see if its object has a method called C<METHOD>, |
| 568 | if it does then a reference to the sub is returned; if it does not then |
| 569 | I<undef> is returned. |
| 570 | |
| 571 | =item VERSION( [NEED] ) |
| 572 | |
| 573 | C<VERSION> returns the version number of the class (package). If the |
| 574 | NEED argument is given then it will check that the current version (as |
| 575 | defined by the $VERSION variable in the given package) not less than |
| 576 | NEED; it will die if this is not the case. This method is normally |
| 577 | called as a class method. This method is called automatically by the |
| 578 | C<VERSION> form of C<use>. |
| 579 | |
| 580 | use A 1.2 qw(some imported subs); |
| 581 | # implies: |
| 582 | A->VERSION(1.2); |
| 583 | |
| 584 | =back |
| 585 | |
| 586 | B<NOTE:> C<can> directly uses Perl's internal code for method lookup, and |
| 587 | C<isa> uses a very similar method and caching strategy. This may cause |
| 588 | strange effects if the Perl code dynamically changes @ISA in any package. |
| 589 | |
| 590 | You may add other methods to the UNIVERSAL class via Perl or XS code. |
| 591 | You do not need to C<use UNIVERSAL> in order to make these methods |
| 592 | available to your program. This is necessary only if you wish to |
| 593 | have C<isa> available as a plain subroutine in the current package. |
| 594 | |
| 595 | =head2 TIEHANDLE now supported |
| 596 | |
| 597 | See L<perltie> for other kinds of tie()s. |
| 598 | |
| 599 | =over 4 |
| 600 | |
| 601 | =item TIEHANDLE classname, LIST |
| 602 | |
| 603 | This is the constructor for the class. That means it is expected to |
| 604 | return an object of some sort. The reference can be used to |
| 605 | hold some internal information. |
| 606 | |
| 607 | sub TIEHANDLE { |
| 608 | print "<shout>\n"; |
| 609 | my $i; |
| 610 | return bless \$i, shift; |
| 611 | } |
| 612 | |
| 613 | =item PRINT this, LIST |
| 614 | |
| 615 | This method will be triggered every time the tied handle is printed to. |
| 616 | Beyond its self reference it also expects the list that was passed to |
| 617 | the print function. |
| 618 | |
| 619 | sub PRINT { |
| 620 | $r = shift; |
| 621 | $$r++; |
| 622 | return print join( $, => map {uc} @_), $\; |
| 623 | } |
| 624 | |
| 625 | =item PRINTF this, LIST |
| 626 | |
| 627 | This method will be triggered every time the tied handle is printed to |
| 628 | with the C<printf()> function. |
| 629 | Beyond its self reference it also expects the format and list that was |
| 630 | passed to the printf function. |
| 631 | |
| 632 | sub PRINTF { |
| 633 | shift; |
| 634 | my $fmt = shift; |
| 635 | print sprintf($fmt, @_)."\n"; |
| 636 | } |
| 637 | |
| 638 | =item READ this LIST |
| 639 | |
| 640 | This method will be called when the handle is read from via the C<read> |
| 641 | or C<sysread> functions. |
| 642 | |
| 643 | sub READ { |
| 644 | $r = shift; |
| 645 | my($buf,$len,$offset) = @_; |
| 646 | print "READ called, \$buf=$buf, \$len=$len, \$offset=$offset"; |
| 647 | } |
| 648 | |
| 649 | =item READLINE this |
| 650 | |
| 651 | This method will be called when the handle is read from. The method |
| 652 | should return undef when there is no more data. |
| 653 | |
| 654 | sub READLINE { |
| 655 | $r = shift; |
| 656 | return "PRINT called $$r times\n" |
| 657 | } |
| 658 | |
| 659 | =item GETC this |
| 660 | |
| 661 | This method will be called when the C<getc> function is called. |
| 662 | |
| 663 | sub GETC { print "Don't GETC, Get Perl"; return "a"; } |
| 664 | |
| 665 | =item DESTROY this |
| 666 | |
| 667 | As with the other types of ties, this method will be called when the |
| 668 | tied handle is about to be destroyed. This is useful for debugging and |
| 669 | possibly for cleaning up. |
| 670 | |
| 671 | sub DESTROY { |
| 672 | print "</shout>\n"; |
| 673 | } |
| 674 | |
| 675 | =back |
| 676 | |
| 677 | =head2 Malloc enhancements |
| 678 | |
| 679 | If perl is compiled with the malloc included with the perl distribution |
| 680 | (that is, if C<perl -V:d_mymalloc> is 'define') then you can print |
| 681 | memory statistics at runtime by running Perl thusly: |
| 682 | |
| 683 | env PERL_DEBUG_MSTATS=2 perl your_script_here |
| 684 | |
| 685 | The value of 2 means to print statistics after compilation and on |
| 686 | exit; with a value of 1, the statistics are printed only on exit. |
| 687 | (If you want the statistics at an arbitrary time, you'll need to |
| 688 | install the optional module Devel::Peek.) |
| 689 | |
| 690 | Three new compilation flags are recognized by malloc.c. (They have no |
| 691 | effect if perl is compiled with system malloc().) |
| 692 | |
| 693 | =over 4 |
| 694 | |
| 695 | =item -DPERL_EMERGENCY_SBRK |
| 696 | |
| 697 | If this macro is defined, running out of memory need not be a fatal |
| 698 | error: a memory pool can allocated by assigning to the special |
| 699 | variable C<$^M>. See L<"$^M">. |
| 700 | |
| 701 | =item -DPACK_MALLOC |
| 702 | |
| 703 | Perl memory allocation is by bucket with sizes close to powers of two. |
| 704 | Because of these malloc overhead may be big, especially for data of |
| 705 | size exactly a power of two. If C<PACK_MALLOC> is defined, perl uses |
| 706 | a slightly different algorithm for small allocations (up to 64 bytes |
| 707 | long), which makes it possible to have overhead down to 1 byte for |
| 708 | allocations which are powers of two (and appear quite often). |
| 709 | |
| 710 | Expected memory savings (with 8-byte alignment in C<alignbytes>) is |
| 711 | about 20% for typical Perl usage. Expected slowdown due to additional |
| 712 | malloc overhead is in fractions of a percent (hard to measure, because |
| 713 | of the effect of saved memory on speed). |
| 714 | |
| 715 | =item -DTWO_POT_OPTIMIZE |
| 716 | |
| 717 | Similarly to C<PACK_MALLOC>, this macro improves allocations of data |
| 718 | with size close to a power of two; but this works for big allocations |
| 719 | (starting with 16K by default). Such allocations are typical for big |
| 720 | hashes and special-purpose scripts, especially image processing. |
| 721 | |
| 722 | On recent systems, the fact that perl requires 2M from system for 1M |
| 723 | allocation will not affect speed of execution, since the tail of such |
| 724 | a chunk is not going to be touched (and thus will not require real |
| 725 | memory). However, it may result in a premature out-of-memory error. |
| 726 | So if you will be manipulating very large blocks with sizes close to |
| 727 | powers of two, it would be wise to define this macro. |
| 728 | |
| 729 | Expected saving of memory is 0-100% (100% in applications which |
| 730 | require most memory in such 2**n chunks); expected slowdown is |
| 731 | negligible. |
| 732 | |
| 733 | =back |
| 734 | |
| 735 | =head2 Miscellaneous efficiency enhancements |
| 736 | |
| 737 | Functions that have an empty prototype and that do nothing but return |
| 738 | a fixed value are now inlined (e.g. C<sub PI () { 3.14159 }>). |
| 739 | |
| 740 | Each unique hash key is only allocated once, no matter how many hashes |
| 741 | have an entry with that key. So even if you have 100 copies of the |
| 742 | same hash, the hash keys never have to be reallocated. |
| 743 | |
| 744 | =head1 Support for More Operating Systems |
| 745 | |
| 746 | Support for the following operating systems is new in Perl 5.004. |
| 747 | |
| 748 | =head2 Win32 |
| 749 | |
| 750 | Perl 5.004 now includes support for building a "native" perl under |
| 751 | Windows NT, using the Microsoft Visual C++ compiler (versions 2.0 |
| 752 | and above) or the Borland C++ compiler (versions 5.02 and above). |
| 753 | The resulting perl can be used under Windows 95 (if it |
| 754 | is installed in the same directory locations as it got installed |
| 755 | in Windows NT). This port includes support for perl extension |
| 756 | building tools like L<MakeMaker> and L<h2xs>, so that many extensions |
| 757 | available on the Comprehensive Perl Archive Network (CPAN) can now be |
| 758 | readily built under Windows NT. See http://www.perl.com/ for more |
| 759 | information on CPAN and F<README.win32> in the perl distribution for more |
| 760 | details on how to get started with building this port. |
| 761 | |
| 762 | There is also support for building perl under the Cygwin32 environment. |
| 763 | Cygwin32 is a set of GNU tools that make it possible to compile and run |
| 764 | many Unix programs under Windows NT by providing a mostly Unix-like |
| 765 | interface for compilation and execution. See F<README.cygwin32> in the |
| 766 | perl distribution for more details on this port and how to obtain the |
| 767 | Cygwin32 toolkit. |
| 768 | |
| 769 | =head2 Plan 9 |
| 770 | |
| 771 | See F<README.plan9> in the perl distribution. |
| 772 | |
| 773 | =head2 QNX |
| 774 | |
| 775 | See F<README.qnx> in the perl distribution. |
| 776 | |
| 777 | =head2 AmigaOS |
| 778 | |
| 779 | See F<README.amigaos> in the perl distribution. |
| 780 | |
| 781 | =head1 Pragmata |
| 782 | |
| 783 | Six new pragmatic modules exist: |
| 784 | |
| 785 | =over 4 |
| 786 | |
| 787 | =item use autouse MODULE => qw(sub1 sub2 sub3) |
| 788 | |
| 789 | Defers C<require MODULE> until someone calls one of the specified |
| 790 | subroutines (which must be exported by MODULE). This pragma should be |
| 791 | used with caution, and only when necessary. |
| 792 | |
| 793 | =item use blib |
| 794 | |
| 795 | =item use blib 'dir' |
| 796 | |
| 797 | Looks for MakeMaker-like I<'blib'> directory structure starting in |
| 798 | I<dir> (or current directory) and working back up to five levels of |
| 799 | parent directories. |
| 800 | |
| 801 | Intended for use on command line with B<-M> option as a way of testing |
| 802 | arbitrary scripts against an uninstalled version of a package. |
| 803 | |
| 804 | =item use constant NAME => VALUE |
| 805 | |
| 806 | Provides a convenient interface for creating compile-time constants, |
| 807 | See L<perlsub/"Constant Functions">. |
| 808 | |
| 809 | =item use locale |
| 810 | |
| 811 | Tells the compiler to enable (or disable) the use of POSIX locales for |
| 812 | builtin operations. |
| 813 | |
| 814 | When C<use locale> is in effect, the current LC_CTYPE locale is used |
| 815 | for regular expressions and case mapping; LC_COLLATE for string |
| 816 | ordering; and LC_NUMERIC for numeric formatting in printf and sprintf |
| 817 | (but B<not> in print). LC_NUMERIC is always used in write, since |
| 818 | lexical scoping of formats is problematic at best. |
| 819 | |
| 820 | Each C<use locale> or C<no locale> affects statements to the end of |
| 821 | the enclosing BLOCK or, if not inside a BLOCK, to the end of the |
| 822 | current file. Locales can be switched and queried with |
| 823 | POSIX::setlocale(). |
| 824 | |
| 825 | See L<perllocale> for more information. |
| 826 | |
| 827 | =item use ops |
| 828 | |
| 829 | Disable unsafe opcodes, or any named opcodes, when compiling Perl code. |
| 830 | |
| 831 | =item use vmsish |
| 832 | |
| 833 | Enable VMS-specific language features. Currently, there are three |
| 834 | VMS-specific features available: 'status', which makes C<$?> and |
| 835 | C<system> return genuine VMS status values instead of emulating POSIX; |
| 836 | 'exit', which makes C<exit> take a genuine VMS status value instead of |
| 837 | assuming that C<exit 1> is an error; and 'time', which makes all times |
| 838 | relative to the local time zone, in the VMS tradition. |
| 839 | |
| 840 | =back |
| 841 | |
| 842 | =head1 Modules |
| 843 | |
| 844 | =head2 Required Updates |
| 845 | |
| 846 | Though Perl 5.004 is compatible with almost all modules that work |
| 847 | with Perl 5.003, there are a few exceptions: |
| 848 | |
| 849 | Module Required Version for Perl 5.004 |
| 850 | ------ ------------------------------- |
| 851 | Filter Filter-1.12 |
| 852 | LWP libwww-perl-5.08 |
| 853 | Tk Tk400.202 (-w makes noise) |
| 854 | |
| 855 | Also, the majordomo mailing list program, version 1.94.1, doesn't work |
| 856 | with Perl 5.004 (nor with perl 4), because it executes an invalid |
| 857 | regular expression. This bug is fixed in majordomo version 1.94.2. |
| 858 | |
| 859 | =head2 Installation directories |
| 860 | |
| 861 | The I<installperl> script now places the Perl source files for |
| 862 | extensions in the architecture-specific library directory, which is |
| 863 | where the shared libraries for extensions have always been. This |
| 864 | change is intended to allow administrators to keep the Perl 5.004 |
| 865 | library directory unchanged from a previous version, without running |
| 866 | the risk of binary incompatibility between extensions' Perl source and |
| 867 | shared libraries. |
| 868 | |
| 869 | =head2 Module information summary |
| 870 | |
| 871 | Brand new modules, arranged by topic rather than strictly |
| 872 | alphabetically: |
| 873 | |
| 874 | CGI.pm Web server interface ("Common Gateway Interface") |
| 875 | CGI/Apache.pm Support for Apache's Perl module |
| 876 | CGI/Carp.pm Log server errors with helpful context |
| 877 | CGI/Fast.pm Support for FastCGI (persistent server process) |
| 878 | CGI/Push.pm Support for server push |
| 879 | CGI/Switch.pm Simple interface for multiple server types |
| 880 | |
| 881 | CPAN Interface to Comprehensive Perl Archive Network |
| 882 | CPAN::FirstTime Utility for creating CPAN configuration file |
| 883 | CPAN::Nox Runs CPAN while avoiding compiled extensions |
| 884 | |
| 885 | IO.pm Top-level interface to IO::* classes |
| 886 | IO/File.pm IO::File extension Perl module |
| 887 | IO/Handle.pm IO::Handle extension Perl module |
| 888 | IO/Pipe.pm IO::Pipe extension Perl module |
| 889 | IO/Seekable.pm IO::Seekable extension Perl module |
| 890 | IO/Select.pm IO::Select extension Perl module |
| 891 | IO/Socket.pm IO::Socket extension Perl module |
| 892 | |
| 893 | Opcode.pm Disable named opcodes when compiling Perl code |
| 894 | |
| 895 | ExtUtils/Embed.pm Utilities for embedding Perl in C programs |
| 896 | ExtUtils/testlib.pm Fixes up @INC to use just-built extension |
| 897 | |
| 898 | FindBin.pm Find path of currently executing program |
| 899 | |
| 900 | Class/Struct.pm Declare struct-like datatypes as Perl classes |
| 901 | File/stat.pm By-name interface to Perl's builtin stat |
| 902 | Net/hostent.pm By-name interface to Perl's builtin gethost* |
| 903 | Net/netent.pm By-name interface to Perl's builtin getnet* |
| 904 | Net/protoent.pm By-name interface to Perl's builtin getproto* |
| 905 | Net/servent.pm By-name interface to Perl's builtin getserv* |
| 906 | Time/gmtime.pm By-name interface to Perl's builtin gmtime |
| 907 | Time/localtime.pm By-name interface to Perl's builtin localtime |
| 908 | Time/tm.pm Internal object for Time::{gm,local}time |
| 909 | User/grent.pm By-name interface to Perl's builtin getgr* |
| 910 | User/pwent.pm By-name interface to Perl's builtin getpw* |
| 911 | |
| 912 | Tie/RefHash.pm Base class for tied hashes with references as keys |
| 913 | |
| 914 | UNIVERSAL.pm Base class for *ALL* classes |
| 915 | |
| 916 | =head2 Fcntl |
| 917 | |
| 918 | New constants in the existing Fcntl modules are now supported, |
| 919 | provided that your operating system happens to support them: |
| 920 | |
| 921 | F_GETOWN F_SETOWN |
| 922 | O_ASYNC O_DEFER O_DSYNC O_FSYNC O_SYNC |
| 923 | O_EXLOCK O_SHLOCK |
| 924 | |
| 925 | These constants are intended for use with the Perl operators sysopen() |
| 926 | and fcntl() and the basic database modules like SDBM_File. For the |
| 927 | exact meaning of these and other Fcntl constants please refer to your |
| 928 | operating system's documentation for fcntl() and open(). |
| 929 | |
| 930 | In addition, the Fcntl module now provides these constants for use |
| 931 | with the Perl operator flock(): |
| 932 | |
| 933 | LOCK_SH LOCK_EX LOCK_NB LOCK_UN |
| 934 | |
| 935 | These constants are defined in all environments (because where there is |
| 936 | no flock() system call, Perl emulates it). However, for historical |
| 937 | reasons, these constants are not exported unless they are explicitly |
| 938 | requested with the ":flock" tag (e.g. C<use Fcntl ':flock'>). |
| 939 | |
| 940 | =head2 IO |
| 941 | |
| 942 | The IO module provides a simple mechanism to load all the IO modules at one |
| 943 | go. Currently this includes: |
| 944 | |
| 945 | IO::Handle |
| 946 | IO::Seekable |
| 947 | IO::File |
| 948 | IO::Pipe |
| 949 | IO::Socket |
| 950 | |
| 951 | For more information on any of these modules, please see its |
| 952 | respective documentation. |
| 953 | |
| 954 | =head2 Math::Complex |
| 955 | |
| 956 | The Math::Complex module has been totally rewritten, and now supports |
| 957 | more operations. These are overloaded: |
| 958 | |
| 959 | + - * / ** <=> neg ~ abs sqrt exp log sin cos atan2 "" (stringify) |
| 960 | |
| 961 | And these functions are now exported: |
| 962 | |
| 963 | pi i Re Im arg |
| 964 | log10 logn ln cbrt root |
| 965 | tan |
| 966 | csc sec cot |
| 967 | asin acos atan |
| 968 | acsc asec acot |
| 969 | sinh cosh tanh |
| 970 | csch sech coth |
| 971 | asinh acosh atanh |
| 972 | acsch asech acoth |
| 973 | cplx cplxe |
| 974 | |
| 975 | =head2 Math::Trig |
| 976 | |
| 977 | This new module provides a simpler interface to parts of Math::Complex for |
| 978 | those who need trigonometric functions only for real numbers. |
| 979 | |
| 980 | =head2 DB_File |
| 981 | |
| 982 | There have been quite a few changes made to DB_File. Here are a few of |
| 983 | the highlights: |
| 984 | |
| 985 | =over 4 |
| 986 | |
| 987 | =item * |
| 988 | |
| 989 | Fixed a handful of bugs. |
| 990 | |
| 991 | =item * |
| 992 | |
| 993 | By public demand, added support for the standard hash function exists(). |
| 994 | |
| 995 | =item * |
| 996 | |
| 997 | Made it compatible with Berkeley DB 1.86. |
| 998 | |
| 999 | =item * |
| 1000 | |
| 1001 | Made negative subscripts work with RECNO interface. |
| 1002 | |
| 1003 | =item * |
| 1004 | |
| 1005 | Changed the default flags from O_RDWR to O_CREAT|O_RDWR and the default |
| 1006 | mode from 0640 to 0666. |
| 1007 | |
| 1008 | =item * |
| 1009 | |
| 1010 | Made DB_File automatically import the open() constants (O_RDWR, |
| 1011 | O_CREAT etc.) from Fcntl, if available. |
| 1012 | |
| 1013 | =item * |
| 1014 | |
| 1015 | Updated documentation. |
| 1016 | |
| 1017 | =back |
| 1018 | |
| 1019 | Refer to the HISTORY section in DB_File.pm for a complete list of |
| 1020 | changes. Everything after DB_File 1.01 has been added since 5.003. |
| 1021 | |
| 1022 | =head2 Net::Ping |
| 1023 | |
| 1024 | Major rewrite - support added for both udp echo and real icmp pings. |
| 1025 | |
| 1026 | =head2 Object-oriented overrides for builtin operators |
| 1027 | |
| 1028 | Many of the Perl builtins returning lists now have |
| 1029 | object-oriented overrides. These are: |
| 1030 | |
| 1031 | File::stat |
| 1032 | Net::hostent |
| 1033 | Net::netent |
| 1034 | Net::protoent |
| 1035 | Net::servent |
| 1036 | Time::gmtime |
| 1037 | Time::localtime |
| 1038 | User::grent |
| 1039 | User::pwent |
| 1040 | |
| 1041 | For example, you can now say |
| 1042 | |
| 1043 | use File::stat; |
| 1044 | use User::pwent; |
| 1045 | $his = (stat($filename)->st_uid == pwent($whoever)->pw_uid); |
| 1046 | |
| 1047 | =head1 Utility Changes |
| 1048 | |
| 1049 | =head2 pod2html |
| 1050 | |
| 1051 | =over 4 |
| 1052 | |
| 1053 | =item Sends converted HTML to standard output |
| 1054 | |
| 1055 | The I<pod2html> utility included with Perl 5.004 is entirely new. |
| 1056 | By default, it sends the converted HTML to its standard output, |
| 1057 | instead of writing it to a file like Perl 5.003's I<pod2html> did. |
| 1058 | Use the B<--outfile=FILENAME> option to write to a file. |
| 1059 | |
| 1060 | =back |
| 1061 | |
| 1062 | =head2 xsubpp |
| 1063 | |
| 1064 | =over 4 |
| 1065 | |
| 1066 | =item C<void> XSUBs now default to returning nothing |
| 1067 | |
| 1068 | Due to a documentation/implementation bug in previous versions of |
| 1069 | Perl, XSUBs with a return type of C<void> have actually been |
| 1070 | returning one value. Usually that value was the GV for the XSUB, |
| 1071 | but sometimes it was some already freed or reused value, which would |
| 1072 | sometimes lead to program failure. |
| 1073 | |
| 1074 | In Perl 5.004, if an XSUB is declared as returning C<void>, it |
| 1075 | actually returns no value, i.e. an empty list (though there is a |
| 1076 | backward-compatibility exception; see below). If your XSUB really |
| 1077 | does return an SV, you should give it a return type of C<SV *>. |
| 1078 | |
| 1079 | For backward compatibility, I<xsubpp> tries to guess whether a |
| 1080 | C<void> XSUB is really C<void> or if it wants to return an C<SV *>. |
| 1081 | It does so by examining the text of the XSUB: if I<xsubpp> finds |
| 1082 | what looks like an assignment to C<ST(0)>, it assumes that the |
| 1083 | XSUB's return type is really C<SV *>. |
| 1084 | |
| 1085 | =back |
| 1086 | |
| 1087 | =head1 C Language API Changes |
| 1088 | |
| 1089 | =over 4 |
| 1090 | |
| 1091 | =item C<gv_fetchmethod> and C<perl_call_sv> |
| 1092 | |
| 1093 | The C<gv_fetchmethod> function finds a method for an object, just like |
| 1094 | in Perl 5.003. The GV it returns may be a method cache entry. |
| 1095 | However, in Perl 5.004, method cache entries are not visible to users; |
| 1096 | therefore, they can no longer be passed directly to C<perl_call_sv>. |
| 1097 | Instead, you should use the C<GvCV> macro on the GV to extract its CV, |
| 1098 | and pass the CV to C<perl_call_sv>. |
| 1099 | |
| 1100 | The most likely symptom of passing the result of C<gv_fetchmethod> to |
| 1101 | C<perl_call_sv> is Perl's producing an "Undefined subroutine called" |
| 1102 | error on the I<second> call to a given method (since there is no cache |
| 1103 | on the first call). |
| 1104 | |
| 1105 | =item C<perl_eval_pv> |
| 1106 | |
| 1107 | A new function handy for eval'ing strings of Perl code inside C code. |
| 1108 | This function returns the value from the eval statement, which can |
| 1109 | be used instead of fetching globals from the symbol table. See |
| 1110 | L<perlguts>, L<perlembed> and L<perlcall> for details and examples. |
| 1111 | |
| 1112 | =item Extended API for manipulating hashes |
| 1113 | |
| 1114 | Internal handling of hash keys has changed. The old hashtable API is |
| 1115 | still fully supported, and will likely remain so. The additions to the |
| 1116 | API allow passing keys as C<SV*>s, so that C<tied> hashes can be given |
| 1117 | real scalars as keys rather than plain strings (nontied hashes still |
| 1118 | can only use strings as keys). New extensions must use the new hash |
| 1119 | access functions and macros if they wish to use C<SV*> keys. These |
| 1120 | additions also make it feasible to manipulate C<HE*>s (hash entries), |
| 1121 | which can be more efficient. See L<perlguts> for details. |
| 1122 | |
| 1123 | =back |
| 1124 | |
| 1125 | =head1 Documentation Changes |
| 1126 | |
| 1127 | Many of the base and library pods were updated. These |
| 1128 | new pods are included in section 1: |
| 1129 | |
| 1130 | =over 4 |
| 1131 | |
| 1132 | =item L<perldelta> |
| 1133 | |
| 1134 | This document. |
| 1135 | |
| 1136 | =item L<perlfaq> |
| 1137 | |
| 1138 | Frequently asked questions. |
| 1139 | |
| 1140 | =item L<perllocale> |
| 1141 | |
| 1142 | Locale support (internationalization and localization). |
| 1143 | |
| 1144 | =item L<perltoot> |
| 1145 | |
| 1146 | Tutorial on Perl OO programming. |
| 1147 | |
| 1148 | =item L<perlapio> |
| 1149 | |
| 1150 | Perl internal IO abstraction interface. |
| 1151 | |
| 1152 | =item L<perlmodlib> |
| 1153 | |
| 1154 | Perl module library and recommended practice for module creation. |
| 1155 | Extracted from L<perlmod> (which is much smaller as a result). |
| 1156 | |
| 1157 | =item L<perldebug> |
| 1158 | |
| 1159 | Although not new, this has been massively updated. |
| 1160 | |
| 1161 | =item L<perlsec> |
| 1162 | |
| 1163 | Although not new, this has been massively updated. |
| 1164 | |
| 1165 | =back |
| 1166 | |
| 1167 | =head1 New Diagnostics |
| 1168 | |
| 1169 | Several new conditions will trigger warnings that were |
| 1170 | silent before. Some only affect certain platforms. |
| 1171 | The following new warnings and errors outline these. |
| 1172 | These messages are classified as follows (listed in |
| 1173 | increasing order of desperation): |
| 1174 | |
| 1175 | (W) A warning (optional). |
| 1176 | (D) A deprecation (optional). |
| 1177 | (S) A severe warning (mandatory). |
| 1178 | (F) A fatal error (trappable). |
| 1179 | (P) An internal error you should never see (trappable). |
| 1180 | (X) A very fatal error (nontrappable). |
| 1181 | (A) An alien error message (not generated by Perl). |
| 1182 | |
| 1183 | =over 4 |
| 1184 | |
| 1185 | =item "my" variable %s masks earlier declaration in same scope |
| 1186 | |
| 1187 | (W) A lexical variable has been redeclared in the same scope, effectively |
| 1188 | eliminating all access to the previous instance. This is almost always |
| 1189 | a typographical error. Note that the earlier variable will still exist |
| 1190 | until the end of the scope or until all closure referents to it are |
| 1191 | destroyed. |
| 1192 | |
| 1193 | =item %s argument is not a HASH element or slice |
| 1194 | |
| 1195 | (F) The argument to delete() must be either a hash element, such as |
| 1196 | |
| 1197 | $foo{$bar} |
| 1198 | $ref->[12]->{"susie"} |
| 1199 | |
| 1200 | or a hash slice, such as |
| 1201 | |
| 1202 | @foo{$bar, $baz, $xyzzy} |
| 1203 | @{$ref->[12]}{"susie", "queue"} |
| 1204 | |
| 1205 | =item Allocation too large: %lx |
| 1206 | |
| 1207 | (X) You can't allocate more than 64K on an MS-DOS machine. |
| 1208 | |
| 1209 | =item Allocation too large |
| 1210 | |
| 1211 | (F) You can't allocate more than 2^31+"small amount" bytes. |
| 1212 | |
| 1213 | =item Applying %s to %s will act on scalar(%s) |
| 1214 | |
| 1215 | (W) The pattern match (//), substitution (s///), and transliteration (tr///) |
| 1216 | operators work on scalar values. If you apply one of them to an array |
| 1217 | or a hash, it will convert the array or hash to a scalar value (the |
| 1218 | length of an array or the population info of a hash) and then work on |
| 1219 | that scalar value. This is probably not what you meant to do. See |
| 1220 | L<perlfunc/grep> and L<perlfunc/map> for alternatives. |
| 1221 | |
| 1222 | =item Attempt to free nonexistent shared string |
| 1223 | |
| 1224 | (P) Perl maintains a reference counted internal table of strings to |
| 1225 | optimize the storage and access of hash keys and other strings. This |
| 1226 | indicates someone tried to decrement the reference count of a string |
| 1227 | that can no longer be found in the table. |
| 1228 | |
| 1229 | =item Attempt to use reference as lvalue in substr |
| 1230 | |
| 1231 | (W) You supplied a reference as the first argument to substr() used |
| 1232 | as an lvalue, which is pretty strange. Perhaps you forgot to |
| 1233 | dereference it first. See L<perlfunc/substr>. |
| 1234 | |
| 1235 | =item Bareword "%s" refers to nonexistent package |
| 1236 | |
| 1237 | (W) You used a qualified bareword of the form C<Foo::>, but |
| 1238 | the compiler saw no other uses of that namespace before that point. |
| 1239 | Perhaps you need to predeclare a package? |
| 1240 | |
| 1241 | =item Can't redefine active sort subroutine %s |
| 1242 | |
| 1243 | (F) Perl optimizes the internal handling of sort subroutines and keeps |
| 1244 | pointers into them. You tried to redefine one such sort subroutine when it |
| 1245 | was currently active, which is not allowed. If you really want to do |
| 1246 | this, you should write C<sort { &func } @x> instead of C<sort func @x>. |
| 1247 | |
| 1248 | =item Can't use bareword ("%s") as %s ref while "strict refs" in use |
| 1249 | |
| 1250 | (F) Only hard references are allowed by "strict refs". Symbolic references |
| 1251 | are disallowed. See L<perlref>. |
| 1252 | |
| 1253 | =item Cannot resolve method `%s' overloading `%s' in package `%s' |
| 1254 | |
| 1255 | (P) Internal error trying to resolve overloading specified by a method |
| 1256 | name (as opposed to a subroutine reference). |
| 1257 | |
| 1258 | =item Constant subroutine %s redefined |
| 1259 | |
| 1260 | (S) You redefined a subroutine which had previously been eligible for |
| 1261 | inlining. See L<perlsub/"Constant Functions"> for commentary and |
| 1262 | workarounds. |
| 1263 | |
| 1264 | =item Constant subroutine %s undefined |
| 1265 | |
| 1266 | (S) You undefined a subroutine which had previously been eligible for |
| 1267 | inlining. See L<perlsub/"Constant Functions"> for commentary and |
| 1268 | workarounds. |
| 1269 | |
| 1270 | =item Copy method did not return a reference |
| 1271 | |
| 1272 | (F) The method which overloads "=" is buggy. See L<overload/Copy Constructor>. |
| 1273 | |
| 1274 | =item Died |
| 1275 | |
| 1276 | (F) You passed die() an empty string (the equivalent of C<die "">) or |
| 1277 | you called it with no args and both C<$@> and C<$_> were empty. |
| 1278 | |
| 1279 | =item Exiting pseudo-block via %s |
| 1280 | |
| 1281 | (W) You are exiting a rather special block construct (like a sort block or |
| 1282 | subroutine) by unconventional means, such as a goto, or a loop control |
| 1283 | statement. See L<perlfunc/sort>. |
| 1284 | |
| 1285 | =item Identifier too long |
| 1286 | |
| 1287 | (F) Perl limits identifiers (names for variables, functions, etc.) to |
| 1288 | 252 characters for simple names, somewhat more for compound names (like |
| 1289 | C<$A::B>). You've exceeded Perl's limits. Future versions of Perl are |
| 1290 | likely to eliminate these arbitrary limitations. |
| 1291 | |
| 1292 | =item Illegal character %s (carriage return) |
| 1293 | |
| 1294 | (F) A carriage return character was found in the input. This is an |
| 1295 | error, and not a warning, because carriage return characters can break |
| 1296 | multi-line strings, including here documents (e.g., C<print <<EOF;>). |
| 1297 | |
| 1298 | =item Illegal switch in PERL5OPT: %s |
| 1299 | |
| 1300 | (X) The PERL5OPT environment variable may only be used to set the |
| 1301 | following switches: B<-[DIMUdmw]>. |
| 1302 | |
| 1303 | =item Integer overflow in hex number |
| 1304 | |
| 1305 | (S) The literal hex number you have specified is too big for your |
| 1306 | architecture. On a 32-bit architecture the largest hex literal is |
| 1307 | 0xFFFFFFFF. |
| 1308 | |
| 1309 | =item Integer overflow in octal number |
| 1310 | |
| 1311 | (S) The literal octal number you have specified is too big for your |
| 1312 | architecture. On a 32-bit architecture the largest octal literal is |
| 1313 | 037777777777. |
| 1314 | |
| 1315 | =item internal error: glob failed |
| 1316 | |
| 1317 | (P) Something went wrong with the external program(s) used for C<glob> |
| 1318 | and C<< <*.c> >>. This may mean that your csh (C shell) is |
| 1319 | broken. If so, you should change all of the csh-related variables in |
| 1320 | config.sh: If you have tcsh, make the variables refer to it as if it |
| 1321 | were csh (e.g. C<full_csh='/usr/bin/tcsh'>); otherwise, make them all |
| 1322 | empty (except that C<d_csh> should be C<'undef'>) so that Perl will |
| 1323 | think csh is missing. In either case, after editing config.sh, run |
| 1324 | C<./Configure -S> and rebuild Perl. |
| 1325 | |
| 1326 | =item Invalid conversion in %s: "%s" |
| 1327 | |
| 1328 | (W) Perl does not understand the given format conversion. |
| 1329 | See L<perlfunc/sprintf>. |
| 1330 | |
| 1331 | =item Invalid type in pack: '%s' |
| 1332 | |
| 1333 | (F) The given character is not a valid pack type. See L<perlfunc/pack>. |
| 1334 | |
| 1335 | =item Invalid type in unpack: '%s' |
| 1336 | |
| 1337 | (F) The given character is not a valid unpack type. See L<perlfunc/unpack>. |
| 1338 | |
| 1339 | =item Name "%s::%s" used only once: possible typo |
| 1340 | |
| 1341 | (W) Typographical errors often show up as unique variable names. |
| 1342 | If you had a good reason for having a unique name, then just mention |
| 1343 | it again somehow to suppress the message (the C<use vars> pragma is |
| 1344 | provided for just this purpose). |
| 1345 | |
| 1346 | =item Null picture in formline |
| 1347 | |
| 1348 | (F) The first argument to formline must be a valid format picture |
| 1349 | specification. It was found to be empty, which probably means you |
| 1350 | supplied it an uninitialized value. See L<perlform>. |
| 1351 | |
| 1352 | =item Offset outside string |
| 1353 | |
| 1354 | (F) You tried to do a read/write/send/recv operation with an offset |
| 1355 | pointing outside the buffer. This is difficult to imagine. |
| 1356 | The sole exception to this is that C<sysread()>ing past the buffer |
| 1357 | will extend the buffer and zero pad the new area. |
| 1358 | |
| 1359 | =item Out of memory! |
| 1360 | |
| 1361 | (X|F) The malloc() function returned 0, indicating there was insufficient |
| 1362 | remaining memory (or virtual memory) to satisfy the request. |
| 1363 | |
| 1364 | The request was judged to be small, so the possibility to trap it |
| 1365 | depends on the way Perl was compiled. By default it is not trappable. |
| 1366 | However, if compiled for this, Perl may use the contents of C<$^M> as |
| 1367 | an emergency pool after die()ing with this message. In this case the |
| 1368 | error is trappable I<once>. |
| 1369 | |
| 1370 | =item Out of memory during request for %s |
| 1371 | |
| 1372 | (F) The malloc() function returned 0, indicating there was insufficient |
| 1373 | remaining memory (or virtual memory) to satisfy the request. However, |
| 1374 | the request was judged large enough (compile-time default is 64K), so |
| 1375 | a possibility to shut down by trapping this error is granted. |
| 1376 | |
| 1377 | =item panic: frexp |
| 1378 | |
| 1379 | (P) The library function frexp() failed, making printf("%f") impossible. |
| 1380 | |
| 1381 | =item Possible attempt to put comments in qw() list |
| 1382 | |
| 1383 | (W) qw() lists contain items separated by whitespace; as with literal |
| 1384 | strings, comment characters are not ignored, but are instead treated |
| 1385 | as literal data. (You may have used different delimiters than the |
| 1386 | parentheses shown here; braces are also frequently used.) |
| 1387 | |
| 1388 | You probably wrote something like this: |
| 1389 | |
| 1390 | @list = qw( |
| 1391 | a # a comment |
| 1392 | b # another comment |
| 1393 | ); |
| 1394 | |
| 1395 | when you should have written this: |
| 1396 | |
| 1397 | @list = qw( |
| 1398 | a |
| 1399 | b |
| 1400 | ); |
| 1401 | |
| 1402 | If you really want comments, build your list the |
| 1403 | old-fashioned way, with quotes and commas: |
| 1404 | |
| 1405 | @list = ( |
| 1406 | 'a', # a comment |
| 1407 | 'b', # another comment |
| 1408 | ); |
| 1409 | |
| 1410 | =item Possible attempt to separate words with commas |
| 1411 | |
| 1412 | (W) qw() lists contain items separated by whitespace; therefore commas |
| 1413 | aren't needed to separate the items. (You may have used different |
| 1414 | delimiters than the parentheses shown here; braces are also frequently |
| 1415 | used.) |
| 1416 | |
| 1417 | You probably wrote something like this: |
| 1418 | |
| 1419 | qw! a, b, c !; |
| 1420 | |
| 1421 | which puts literal commas into some of the list items. Write it without |
| 1422 | commas if you don't want them to appear in your data: |
| 1423 | |
| 1424 | qw! a b c !; |
| 1425 | |
| 1426 | =item Scalar value @%s{%s} better written as $%s{%s} |
| 1427 | |
| 1428 | (W) You've used a hash slice (indicated by @) to select a single element of |
| 1429 | a hash. Generally it's better to ask for a scalar value (indicated by $). |
| 1430 | The difference is that C<$foo{&bar}> always behaves like a scalar, both when |
| 1431 | assigning to it and when evaluating its argument, while C<@foo{&bar}> behaves |
| 1432 | like a list when you assign to it, and provides a list context to its |
| 1433 | subscript, which can do weird things if you're expecting only one subscript. |
| 1434 | |
| 1435 | =item Stub found while resolving method `%s' overloading `%s' in %s |
| 1436 | |
| 1437 | (P) Overloading resolution over @ISA tree may be broken by importing stubs. |
| 1438 | Stubs should never be implicitly created, but explicit calls to C<can> |
| 1439 | may break this. |
| 1440 | |
| 1441 | =item Too late for "B<-T>" option |
| 1442 | |
| 1443 | (X) The #! line (or local equivalent) in a Perl script contains the |
| 1444 | B<-T> option, but Perl was not invoked with B<-T> in its argument |
| 1445 | list. This is an error because, by the time Perl discovers a B<-T> in |
| 1446 | a script, it's too late to properly taint everything from the |
| 1447 | environment. So Perl gives up. |
| 1448 | |
| 1449 | =item untie attempted while %d inner references still exist |
| 1450 | |
| 1451 | (W) A copy of the object returned from C<tie> (or C<tied>) was still |
| 1452 | valid when C<untie> was called. |
| 1453 | |
| 1454 | =item Unrecognized character %s |
| 1455 | |
| 1456 | (F) The Perl parser has no idea what to do with the specified character |
| 1457 | in your Perl script (or eval). Perhaps you tried to run a compressed |
| 1458 | script, a binary program, or a directory as a Perl program. |
| 1459 | |
| 1460 | =item Unsupported function fork |
| 1461 | |
| 1462 | (F) Your version of executable does not support forking. |
| 1463 | |
| 1464 | Note that under some systems, like OS/2, there may be different flavors of |
| 1465 | Perl executables, some of which may support fork, some not. Try changing |
| 1466 | the name you call Perl by to C<perl_>, C<perl__>, and so on. |
| 1467 | |
| 1468 | =item Use of "$$<digit>" to mean "${$}<digit>" is deprecated |
| 1469 | |
| 1470 | (D) Perl versions before 5.004 misinterpreted any type marker followed |
| 1471 | by "$" and a digit. For example, "$$0" was incorrectly taken to mean |
| 1472 | "${$}0" instead of "${$0}". This bug is (mostly) fixed in Perl 5.004. |
| 1473 | |
| 1474 | However, the developers of Perl 5.004 could not fix this bug completely, |
| 1475 | because at least two widely-used modules depend on the old meaning of |
| 1476 | "$$0" in a string. So Perl 5.004 still interprets "$$<digit>" in the |
| 1477 | old (broken) way inside strings; but it generates this message as a |
| 1478 | warning. And in Perl 5.005, this special treatment will cease. |
| 1479 | |
| 1480 | =item Value of %s can be "0"; test with defined() |
| 1481 | |
| 1482 | (W) In a conditional expression, you used <HANDLE>, <*> (glob), C<each()>, |
| 1483 | or C<readdir()> as a boolean value. Each of these constructs can return a |
| 1484 | value of "0"; that would make the conditional expression false, which is |
| 1485 | probably not what you intended. When using these constructs in conditional |
| 1486 | expressions, test their values with the C<defined> operator. |
| 1487 | |
| 1488 | =item Variable "%s" may be unavailable |
| 1489 | |
| 1490 | (W) An inner (nested) I<anonymous> subroutine is inside a I<named> |
| 1491 | subroutine, and outside that is another subroutine; and the anonymous |
| 1492 | (innermost) subroutine is referencing a lexical variable defined in |
| 1493 | the outermost subroutine. For example: |
| 1494 | |
| 1495 | sub outermost { my $a; sub middle { sub { $a } } } |
| 1496 | |
| 1497 | If the anonymous subroutine is called or referenced (directly or |
| 1498 | indirectly) from the outermost subroutine, it will share the variable |
| 1499 | as you would expect. But if the anonymous subroutine is called or |
| 1500 | referenced when the outermost subroutine is not active, it will see |
| 1501 | the value of the shared variable as it was before and during the |
| 1502 | *first* call to the outermost subroutine, which is probably not what |
| 1503 | you want. |
| 1504 | |
| 1505 | In these circumstances, it is usually best to make the middle |
| 1506 | subroutine anonymous, using the C<sub {}> syntax. Perl has specific |
| 1507 | support for shared variables in nested anonymous subroutines; a named |
| 1508 | subroutine in between interferes with this feature. |
| 1509 | |
| 1510 | =item Variable "%s" will not stay shared |
| 1511 | |
| 1512 | (W) An inner (nested) I<named> subroutine is referencing a lexical |
| 1513 | variable defined in an outer subroutine. |
| 1514 | |
| 1515 | When the inner subroutine is called, it will probably see the value of |
| 1516 | the outer subroutine's variable as it was before and during the |
| 1517 | *first* call to the outer subroutine; in this case, after the first |
| 1518 | call to the outer subroutine is complete, the inner and outer |
| 1519 | subroutines will no longer share a common value for the variable. In |
| 1520 | other words, the variable will no longer be shared. |
| 1521 | |
| 1522 | Furthermore, if the outer subroutine is anonymous and references a |
| 1523 | lexical variable outside itself, then the outer and inner subroutines |
| 1524 | will I<never> share the given variable. |
| 1525 | |
| 1526 | This problem can usually be solved by making the inner subroutine |
| 1527 | anonymous, using the C<sub {}> syntax. When inner anonymous subs that |
| 1528 | reference variables in outer subroutines are called or referenced, |
| 1529 | they are automatically rebound to the current values of such |
| 1530 | variables. |
| 1531 | |
| 1532 | =item Warning: something's wrong |
| 1533 | |
| 1534 | (W) You passed warn() an empty string (the equivalent of C<warn "">) or |
| 1535 | you called it with no args and C<$_> was empty. |
| 1536 | |
| 1537 | =item Ill-formed logical name |%s| in prime_env_iter |
| 1538 | |
| 1539 | (W) A warning peculiar to VMS. A logical name was encountered when preparing |
| 1540 | to iterate over %ENV which violates the syntactic rules governing logical |
| 1541 | names. Since it cannot be translated normally, it is skipped, and will not |
| 1542 | appear in %ENV. This may be a benign occurrence, as some software packages |
| 1543 | might directly modify logical name tables and introduce nonstandard names, |
| 1544 | or it may indicate that a logical name table has been corrupted. |
| 1545 | |
| 1546 | =item Got an error from DosAllocMem |
| 1547 | |
| 1548 | (P) An error peculiar to OS/2. Most probably you're using an obsolete |
| 1549 | version of Perl, and this should not happen anyway. |
| 1550 | |
| 1551 | =item Malformed PERLLIB_PREFIX |
| 1552 | |
| 1553 | (F) An error peculiar to OS/2. PERLLIB_PREFIX should be of the form |
| 1554 | |
| 1555 | prefix1;prefix2 |
| 1556 | |
| 1557 | or |
| 1558 | |
| 1559 | prefix1 prefix2 |
| 1560 | |
| 1561 | with nonempty prefix1 and prefix2. If C<prefix1> is indeed a prefix |
| 1562 | of a builtin library search path, prefix2 is substituted. The error |
| 1563 | may appear if components are not found, or are too long. See |
| 1564 | "PERLLIB_PREFIX" in F<README.os2>. |
| 1565 | |
| 1566 | =item PERL_SH_DIR too long |
| 1567 | |
| 1568 | (F) An error peculiar to OS/2. PERL_SH_DIR is the directory to find the |
| 1569 | C<sh>-shell in. See "PERL_SH_DIR" in F<README.os2>. |
| 1570 | |
| 1571 | =item Process terminated by SIG%s |
| 1572 | |
| 1573 | (W) This is a standard message issued by OS/2 applications, while *nix |
| 1574 | applications die in silence. It is considered a feature of the OS/2 |
| 1575 | port. One can easily disable this by appropriate sighandlers, see |
| 1576 | L<perlipc/"Signals">. See also "Process terminated by SIGTERM/SIGINT" |
| 1577 | in F<README.os2>. |
| 1578 | |
| 1579 | =back |
| 1580 | |
| 1581 | =head1 BUGS |
| 1582 | |
| 1583 | If you find what you think is a bug, you might check the headers of |
| 1584 | recently posted articles in the comp.lang.perl.misc newsgroup. |
| 1585 | There may also be information at http://www.perl.com/perl/ , the Perl |
| 1586 | Home Page. |
| 1587 | |
| 1588 | If you believe you have an unreported bug, please run the B<perlbug> |
| 1589 | program included with your release. Make sure you trim your bug down |
| 1590 | to a tiny but sufficient test case. Your bug report, along with the |
| 1591 | output of C<perl -V>, will be sent off to <F<perlbug@perl.com>> to be |
| 1592 | analysed by the Perl porting team. |
| 1593 | |
| 1594 | =head1 SEE ALSO |
| 1595 | |
| 1596 | The F<Changes> file for exhaustive details on what changed. |
| 1597 | |
| 1598 | The F<INSTALL> file for how to build Perl. This file has been |
| 1599 | significantly updated for 5.004, so even veteran users should |
| 1600 | look through it. |
| 1601 | |
| 1602 | The F<README> file for general stuff. |
| 1603 | |
| 1604 | The F<Copying> file for copyright information. |
| 1605 | |
| 1606 | =head1 HISTORY |
| 1607 | |
| 1608 | Constructed by Tom Christiansen, grabbing material with permission |
| 1609 | from innumerable contributors, with kibitzing by more than a few Perl |
| 1610 | porters. |
| 1611 | |
| 1612 | Last update: Wed May 14 11:14:09 EDT 1997 |