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Text File | 1998-10-28 | 50.5 KB | 1,321 lines

PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) NNNNAAAAMMMMEEEE perldelta - what's new for perl5.005 DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN This document describes differences between the 5.004 release and this one. AAAAbbbboooouuuutttt tttthhhheeee nnnneeeewwww vvvveeeerrrrssssiiiioooonnnniiiinnnngggg ssssyyyysssstttteeeemmmm Perl is now developed on two tracks: a maintenance track that makes small, safe updates to released production versions with emphasis on compatibility; and a development track that pursues more aggressive evolution. Maintenance releases (which should be considered production quality) have subversion numbers that run from 1 to 49, and development releases (which should be considered "alpha" quality) run from 50 to 99. Perl 5.005 is the combined product of the new dual-track development scheme. IIIInnnnccccoooommmmppppaaaattttiiiibbbblllleeee CCCChhhhaaaannnnggggeeeessss WWWWAAAARRRRNNNNIIIINNNNGGGG:::: TTTThhhhiiiissss vvvveeeerrrrssssiiiioooonnnn iiiissss nnnnooootttt bbbbiiiinnnnaaaarrrryyyy ccccoooommmmppppaaaattttiiiibbbblllleeee wwwwiiiitttthhhh PPPPeeeerrrrllll 5555....000000004444.... Starting with Perl 5.004_50 there were many deep and far- reaching changes to the language internals. If you have dynamically loaded extensions that you built under perl 5.003 or 5.004, you can continue to use them with 5.004, but you will need to rebuild and reinstall those extensions to use them 5.005. See the _I_N_S_T_A_L_L manpage for detailed instructions on how to upgrade. DDDDeeeeffffaaaauuuulllltttt iiiinnnnssssttttaaaallllllllaaaattttiiiioooonnnn ssssttttrrrruuuuccccttttuuuurrrreeee hhhhaaaassss cccchhhhaaaannnnggggeeeedddd The new Configure defaults are designed to allow a smooth upgrade from 5.004 to 5.005, but you should read the _I_N_S_T_A_L_L manpage for a detailed discussion of the changes in order to adapt them to your system. PPPPeeeerrrrllll SSSSoooouuuurrrrcccceeee CCCCoooommmmppppaaaattttiiiibbbbiiiilllliiiittttyyyy When none of the experimental features are enabled, there should be very few user-visible Perl source compatibility issues. If threads are enabled, then some caveats apply. @_ and $_ become lexical variables. The effect of this should be largely transparent to the user, but there are some boundary conditions under which user will need to be aware of the issues. For example, local(@_) results in a "Can't localize lexical variable @_ ..." message. This may be enabled in a future version. Page 1 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) Some new keywords have been introduced. These are generally expected to have very little impact on compatibility. See the section on _N_e_w _I_N_I_T keyword, the section on _N_e_w _l_o_c_k keyword, and the section on _N_e_w _q_r// operator. Certain barewords are now reserved. Use of these will provoke a warning if you have asked for them with the -w switch. See the _o_u_r manpage is now a reserved word. CCCC SSSSoooouuuurrrrcccceeee CCCCoooommmmppppaaaattttiiiibbbbiiiilllliiiittttyyyy There have been a large number of changes in the internals to support the new features in this release. Core sources now require ANSI C compiler An ANSI C compiler is now rrrreeeeqqqquuuuiiiirrrreeeedddd to build perl. See _I_N_S_T_A_L_L. prefix All Perl global variables must now be referenced with an explicit All Perl global variables that are visible for use by extensions now have a PL_ prefix. New extensions should not refer to perl globals by their unqualified names. To preserve sanity, we provide limited backward compatibility for globals that are being widely used like sv_undef and na (which should now be written as PL_sv_undef, PL_na etc.) If you find that your XS extension does not compile anymore because a perl global is not visible, try adding a PL_ prefix to the global and rebuild. It is strongly recommended that all functions in the Perl API that don't begin with perl be referenced with a Perl_ prefix. The bare function names without the Perl_ prefix are supported with macros, but this support may cease in a future release. See the section on _A_P_I _L_I_S_T_I_N_G in the _p_e_r_l_g_u_t_s manpage. Enabling threads has source compatibility issues Perl built with threading enabled requires extensions to use the new dTHR macro to initialize the handle to access per-thread data. If you see a compiler error that talks about the variable thr not being declared (when building a module that has XS code), you need to add dTHR; at the beginning of the block that elicited the error. The API function perl_get_sv("@",FALSE) should be used instead of directly accessing perl globals as GvSV(errgv). The API call is backward compatible with Page 2 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) existing perls and provides source compatibility with threading is enabled. See the section on _A_P_I _C_h_a_n_g_e_s _f_o_r _m_o_r_e _i_n_f_o_r_m_a_t_i_o_n. BBBBiiiinnnnaaaarrrryyyy CCCCoooommmmppppaaaattttiiiibbbbiiiilllliiiittttyyyy This version is NOT binary compatible with older versions. All extensions will need to be recompiled. Further binaries built with threads enabled are incompatible with binaries built without. This should largely be transparent to the user, as all binary incompatible configurations have their own unique architecture name, and extension binaries get installed at unique locations. This allows coexistence of several configurations in the same directory hierarchy. See _I_N_S_T_A_L_L. SSSSeeeeccccuuuurrrriiiittttyyyy ffffiiiixxxxeeeessss mmmmaaaayyyy aaaaffffffffeeeecccctttt ccccoooommmmppppaaaattttiiiibbbbiiiilllliiiittttyyyy A few taint leaks and taint omissions have been corrected. This may lead to "failure" of scripts that used to work with older versions. Compiling with -DINCOMPLETE_TAINTS provides a perl with minimal amounts of changes to the tainting behavior. But note that the resulting perl will have known insecurities. Oneliners with the -e switch do not create temporary files anymore. RRRReeeellllaaaaxxxxeeeedddd nnnneeeewwww mmmmaaaannnnddddaaaattttoooorrrryyyy wwwwaaaarrrrnnnniiiinnnnggggssss iiiinnnnttttrrrroooodddduuuucccceeeedddd iiiinnnn 5555....000000004444 Many new warnings that were introduced in 5.004 have been made optional. Some of these warnings are still present, but perl's new features make them less often a problem. See the section on _N_e_w _D_i_a_g_n_o_s_t_i_c_s. LLLLiiiicccceeeennnnssssiiiinnnngggg Perl has a new Social Contract for contributors. See _P_o_r_t_i_n_g/_C_o_n_t_r_a_c_t. The license included in much of the Perl documentation has changed. Most of the Perl documentation was previously under the implicit GNU General Public License or the Artistic License (at the user's choice). Now much of the documentation unambigously states the terms under which it may be distributed. Those terms are in general much less restrictive than the GNU GPL. See the _p_e_r_l manpage and the individual perl man pages listed therein. CCCCoooorrrreeee CCCChhhhaaaannnnggggeeeessss Page 3 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) TTTThhhhrrrreeeeaaaaddddssss WARNING: Threading is considered an eeeexxxxppppeeeerrrriiiimmmmeeeennnnttttaaaallll feature. Details of the implementation may change without notice. There are known limitations and some bugs. These are expected to be fixed in future versions. See the _R_E_A_D_M_E._t_h_r_e_a_d_s manpage. CCCCoooommmmppppiiiilllleeeerrrr WARNING: The Compiler and related tools are considered eeeexxxxppppeeeerrrriiiimmmmeeeennnnttttaaaallll. Features may change without notice, and there are known limitations and bugs. Since the compiler is fully external to perl, the default configuration will build and install it. The Compiler produces three different types of transformations of a perl program. The C backend generates C code that captures perl's state just before execution begins. It eliminates the compile-time overheads of the regular perl interpreter, but the run-time performance remains comparatively the same. The CC backend generates optimized C code equivalent to the code path at run-time. The CC backend has greater potential for big optimizations, but only a few optimizations are implemented currently. The Bytecode backend generates a platform independent bytecode representation of the interpreter's state just before execution. Thus, the Bytecode back end also eliminates much of the compilation overhead of the interpreter. The compiler comes with several valuable utilities. B::Lint is an experimental module to detect and warn about suspicious code, especially the cases that the -w switch does not detect. B::Deparse can be used to demystify perl code, and understand how perl optimizes certain constructs. B::Xref generates cross reference reports of all definition and use of variables, subroutines and formats in a program. B::Showlex show the lexical variables used by a subroutine or file at a glance. perlcc is a simple frontend for compiling perl. See ext/B/README, the section on _B, and the respective compiler modules. Page 4 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) RRRReeeegggguuuullllaaaarrrr EEEExxxxpppprrrreeeessssssssiiiioooonnnnssss Perl's regular expression engine has been seriously overhauled, and many new constructs are supported. Several bugs have been fixed. Here is an itemized summary: Many new and improved optimizations Changes in the RE engine: Unneeded nodes removed; Substrings merged together; New types of nodes to process (SUBEXPR)* and similar expressions quickly, used if the SUBEXPR has no side effects and matches strings of the same length; Better optimizations by lookup for constant substrings; Better search for constants substrings anchored by $ ; Changes in Perl code using RE engine: More optimizations to s/longer/short/; study() was not working; /blah/ may be optimized to an analogue of index() if $& $` $' not seen; Unneeded copying of matched-against string removed; Only matched part of the string is copying if $` $' were not seen; Many bug fixes Note that only the major bug fixes are listed here. See _C_h_a_n_g_e_s for others. Backtracking might not restore start of $3. No feedback if max count for * or + on "complex" subexpression was reached, similarly (but at compile time) for {3,34567} Primitive restrictions on max count introduced to decrease a possibility of a segfault; (ZERO-LENGTH)* could segfault; (ZERO-LENGTH)* was prohibited; Long REs were not allowed; /RE/g could skip matches at the same position after a zero-length match; New regular expression constructs The following new syntax elements are supported: Page 5 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) (?<=RE) (?<!RE) (?{ CODE }) (?i-x) (?i:RE) (?(COND)YES_RE|NO_RE) (?>RE) \z New operator for precompiled regular expressions See the section on _N_e_w _q_r// operator. Other improvements Better debugging output (possibly with colors), even from non-debugging Perl; RE engine code now looks like C, not like assembler; Behaviour of RE modifiable by `use re' directive; Improved documentation; Test suite significantly extended; Syntax [:^upper:] etc., reserved inside character classes; Incompatible changes (?i) localized inside enclosing group; $( is not interpolated into RE any more; /RE/g may match at the same position (with non-zero length) after a zero-length match (bug fix). See the _p_e_r_l_r_e manpage and the _p_e_r_l_o_p manpage. IIIImmmmpppprrrroooovvvveeeedddd _m_a_l_l_o_c() See banner at the beginning of malloc.c for details. QQQQuuuuiiiicccckkkkssssoooorrrrtttt iiiissss iiiinnnntttteeeerrrrnnnnaaaallllllllyyyy iiiimmmmpppplllleeeemmmmeeeennnntttteeeedddd Perl now contains its own highly optimized _q_s_o_r_t() routine. The new _q_s_o_r_t() is resistant to inconsistent comparison functions, so Perl's sort() will not provoke coredumps any more when given poorly written sort subroutines. (Some C library qsort()s that were being used before used to have this problem.) In our testing, the new qsort() required the minimal number of pair-wise compares on average, among all known qsort() implementations. See perlfunc/sort. Page 6 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) RRRReeeelllliiiiaaaabbbblllleeee ssssiiiiggggnnnnaaaallllssss Perl's signal handling is susceptible to random crashes, because signals arrive asynchronously, and the Perl runtime is not reentrant at arbitrary times. However, one experimental implementation of reliable signals is available when threads are enabled. See Thread::Signal. Also see _I_N_S_T_A_L_L for how to build a Perl capable of threads. RRRReeeelllliiiiaaaabbbblllleeee ssssttttaaaacccckkkk ppppooooiiiinnnntttteeeerrrrssss The internals now reallocate the perl stack only at predictable times. In particular, magic calls never trigger reallocations of the stack, because all reentrancy of the runtime is handled using a "stack of stacks". This should improve reliability of cached stack pointers in the internals and in XSUBs. MMMMoooorrrreeee ggggeeeennnneeeerrrroooouuuussss ttttrrrreeeeaaaattttmmmmeeeennnntttt ooooffff ccccaaaarrrrrrrriiiiaaaaggggeeee rrrreeeettttuuuurrrrnnnnssss Perl used to complain if it encountered literal carriage returns in scripts. Now they are mostly treated like whitespace within program text. Inside string literals and here documents, literal carriage returns are ignored if they occur paired with newlines, or get interpreted as newlines if they stand alone. This behavior means that literal carriage returns in files should be avoided. You can get the older, more compatible (but less generous) behavior by defining the preprocessor symbol PERL_STRICT_CR when building perl. Of course, all this has nothing whatever to do with how escapes like \r are handled within strings. Note that this doesn't somehow magically allow you to keep all text files in DOS format. The generous treatment only applies to files that perl itself parses. If your C compiler doesn't allow carriage returns in files, you may still be unable to build modules that need a C compiler. MMMMeeeemmmmoooorrrryyyy lllleeeeaaaakkkkssss substr, pos and vec don't leak memory anymore when used in lvalue context. Many small leaks that impacted applications that embed multiple interpreters have been fixed. BBBBeeeetttttttteeeerrrr ssssuuuuppppppppoooorrrrtttt ffffoooorrrr mmmmuuuullllttttiiiipppplllleeee iiiinnnntttteeeerrrrpppprrrreeeetttteeeerrrrssss The build-time option -DMULTIPLICITY has had many of the details reworked. Some previously global variables that should have been per-interpreter now are. With care, this allows interpreters to call each other. See the PerlInterp extension on CPAN. Page 7 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) BBBBeeeehhhhaaaavvvviiiioooorrrr ooooffff _l_o_c_a_l() on array and hash elements is now well- defined See the section on _T_e_m_p_o_r_a_r_y _V_a_l_u_e_s _v_i_a _l_o_c_a_l() in the _p_e_r_l_s_u_b manpage. %%%%!!!! is transparently tied to the the _E_r_r_n_o manpage module See the _p_e_r_l_v_a_r manpage, and the _E_r_r_n_o manpage. PPPPsssseeeeuuuuddddoooo----hhhhaaaasssshhhheeeessss aaaarrrreeee ssssuuuuppppppppoooorrrrtttteeeedddd See the _p_e_r_l_r_e_f manpage. EEEEXXXXPPPPRRRR ffffoooorrrreeeeaaaacccchhhh EEEEXXXXPPPPRRRR is supported See the _p_e_r_l_s_y_n manpage. KKKKeeeeyyyywwwwoooorrrrddddssss ccccaaaannnn bbbbeeee gggglllloooobbbbaaaallllllllyyyy oooovvvveeeerrrrrrrriiiiddddddddeeeennnn See the _p_e_r_l_s_u_b manpage. $$$$^^^^EEEE is meaningful on Win32 See the _p_e_r_l_v_a_r manpage. ffffoooorrrreeeeaaaacccchhhh ((((1111........1111000000000000000000000000)))) optimized foreach (1..1000000) is now optimized into a counting loop. It does not try to allocate a 1000000-size list anymore. FFFFoooooooo:::::::: can be used as implicitly quoted package name Barewords caused unintuitive behavior when a subroutine with the same name as a package happened to be defined. Thus, new Foo @args, use the result of the call to Foo() instead of Foo being treated as a literal. The recommended way to write barewords in the indirect object slot is new Foo:: @args. Note that the method new() is called with a first argument of Foo, not Foo:: when you do that. eeeexxxxiiiissssttttssss $$$$FFFFoooooooo::::::::{{{{BBBBaaaarrrr::::::::}}}} tests existence of a package It was impossible to test for the existence of a package without actually creating it before. Now exists $Foo::{Bar::} can be used to test if the Foo::Bar namespace has been created. BBBBeeeetttttttteeeerrrr llllooooccccaaaalllleeee ssssuuuuppppppppoooorrrrtttt See the _p_e_r_l_l_o_c_a_l_e manpage. Page 8 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) EEEExxxxppppeeeerrrriiiimmmmeeeennnnttttaaaallll ssssuuuuppppppppoooorrrrtttt ffffoooorrrr 66664444----bbbbiiiitttt ppppllllaaaattttffffoooorrrrmmmmssss Perl5 has always had 64-bit support on systems with 64-bit longs. Starting with 5.005, the beginnings of experimental support for systems with 32-bit long and 64-bit 'long long' integers has been added. If you add -DUSE_LONG_LONG to your ccflags in config.sh (or manually define it in perl.h) then perl will be built with 'long long' support. There will be many compiler warnings, and the resultant perl may not work on all systems. There are many other issues related to third-party extensions and libraries. This option exists to allow people to work on those issues. _p_r_o_t_o_t_y_p_e() returns useful results on builtins See the prototype entry in the _p_e_r_l_f_u_n_c manpage. EEEExxxxtttteeeennnnddddeeeedddd ssssuuuuppppppppoooorrrrtttt ffffoooorrrr eeeexxxxcccceeeeppppttttiiiioooonnnn hhhhaaaannnnddddlllliiiinnnngggg die() now accepts a reference value, and $@ gets set to that value in exception traps. This makes it possible to propagate exception objects. This is an undocumented eeeexxxxppppeeeerrrriiiimmmmeeeennnnttttaaaallll feature. RRRReeee----bbbblllleeeessssssssiiiinnnngggg iiiinnnn _D_E_S_T_R_O_Y() supported for chaining _D_E_S_T_R_O_Y() methods See the Destructors entry in the _p_e_r_l_o_b_j manpage. AAAAllllllll pppprrrriiiinnnnttttffff format conversions are handled internally See the printf entry in the _p_e_r_l_f_u_n_c manpage. NNNNeeeewwww IIIINNNNIIIITTTT keyword INIT subs are like BEGIN and END, but they get run just before the perl runtime begins execution. e.g., the Perl Compiler makes use of INIT blocks to initialize and resolve pointers to XSUBs. NNNNeeeewwww lllloooocccckkkk keyword The lock keyword is the fundamental synchronization primitive in threaded perl. When threads are not enabled, it is currently a noop. To minimize impact on source compatibility this keyword is "weak", i.e., any user-defined subroutine of the same name overrides it, unless a use Thread has been seen. Page 9 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) NNNNeeeewwww qqqqrrrr//////// operator The qr// operator, which is syntactically similar to the other quote-like operators, is used to create precompiled regular expressions. This compiled form can now be explicitly passed around in variables, and interpolated in other regular expressions. See the _p_e_r_l_o_p manpage. oooouuuurrrr is now a reserved word Calling a subroutine with the name our will now provoke a warning when using the -w switch. TTTTiiiieeeedddd aaaarrrrrrrraaaayyyyssss aaaarrrreeee nnnnoooowwww ffffuuuullllllllyyyy ssssuuuuppppppppoooorrrrtttteeeedddd See the _T_i_e::_A_r_r_a_y manpage. TTTTiiiieeeedddd hhhhaaaannnnddddlllleeeessss ssssuuuuppppppppoooorrrrtttt iiiissss bbbbeeeetttttttteeeerrrr Several missing hooks have been added. There is also a new base class for TIEARRAY implementations. See the _T_i_e::_A_r_r_a_y manpage. 4444tttthhhh aaaarrrrgggguuuummmmeeeennnntttt ttttoooo ssssuuuubbbbssssttttrrrr _s_u_b_s_t_r() can now both return and replace in one operation. The optional 4th argument is the replacement string. See the substr entry in the _p_e_r_l_f_u_n_c manpage. NNNNeeeeggggaaaattttiiiivvvveeee LLLLEEEENNNNGGGGTTTTHHHH aaaarrrrgggguuuummmmeeeennnntttt ttttoooo sssspppplllliiiicccceeee _s_p_l_i_c_e() with a negative LENGTH argument now work similar to what the LENGTH did for _s_u_b_s_t_r(). Previously a negative LENGTH was treated as 0. See the splice entry in the _p_e_r_l_f_u_n_c manpage. MMMMaaaaggggiiiicccc llllvvvvaaaalllluuuueeeessss aaaarrrreeee nnnnoooowwww mmmmoooorrrreeee mmmmaaaaggggiiiiccccaaaallll When you say something like substr($x, 5) = "hi", the scalar returned by _s_u_b_s_t_r() is special, in that any modifications to it affect $x. (This is called a 'magic lvalue' because an 'lvalue' is something on the left side of an assignment.) Normally, this is exactly what you would expect to happen, but Perl uses the same magic if you use _s_u_b_s_t_r(), _p_o_s(), or _v_e_c() in a context where they might be modified, like taking a reference with \ or as an argument to a sub that modifies @_. In previous versions, this 'magic' only went one way, but now changes to the scalar the magic refers to ($x in the above example) affect the magic lvalue too. For instance, this code now acts differently: Page 10 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) $x = "hello"; sub printit { $x = "g'bye"; print $_[0], "\n"; } printit(substr($x, 0, 5)); In previous versions, this would print "hello", but it now prints "g'bye". <<<<>>>> nnnnoooowwww rrrreeeeaaaaddddssss iiiinnnn rrrreeeeccccoooorrrrddddssss If $/ is a referenence to an integer, or a scalar that holds an integer, <> will read in records instead of lines. For more info, see the section on $/ in the _p_e_r_l_v_a_r manpage. SSSSuuuuppppppppoooorrrrtttteeeedddd PPPPllllaaaattttffffoooorrrrmmmmssss Configure has many incremental improvements. Site-wide policy for building perl can now be made persistent, via Policy.sh. Configure also records the command-line arguments used in _c_o_n_f_i_g._s_h. NNNNeeeewwww PPPPllllaaaattttffffoooorrrrmmmmssss BeOS is now supported. See the _R_E_A_D_M_E._b_e_o_s manpage. DOS is now supported under the DJGPP tools. See the _R_E_A_D_M_E._d_o_s manpage. MPE/iX is now supported. See the _R_E_A_D_M_E._m_p_e_i_x manpage. MVS (OS390) is now supported. See the _R_E_A_D_M_E._o_s_3_9_0 manpage. CCCChhhhaaaannnnggggeeeessss iiiinnnn eeeexxxxiiiissssttttiiiinnnngggg ssssuuuuppppppppoooorrrrtttt Win32 support has been vastly enhanced. Support for Perl Object, a C++ encapsulation of Perl. GCC and EGCS are now supported on Win32. See _R_E_A_D_M_E._w_i_n_3_2, aka the _p_e_r_l_w_i_n_3_2 manpage. VMS configuration system has been rewritten. See the _R_E_A_D_M_E._v_m_s manpage. The hints files for most Unix platforms have seen incremental improvements. MMMMoooodddduuuulllleeeessss aaaannnndddd PPPPrrrraaaaggggmmmmaaaattttaaaa NNNNeeeewwww MMMMoooodddduuuulllleeeessss B Perl compiler and tools. See the section on _B. Page 11 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) Data::Dumper A module to pretty print Perl data. See the _D_a_t_a::_D_u_m_p_e_r manpage. Errno A module to look up errors more conveniently. See the _E_r_r_n_o manpage. File::Spec A portable API for file operations. ExtUtils::Installed Query and manage installed modules. ExtUtils::Packlist Manipulate .packlist files. Fatal Make functions/builtins succeed or die. IPC::SysV Constants and other support infrastructure for System V IPC operations in perl. Test A framework for writing testsuites. Tie::Array Base class for tied arrays. Tie::Handle Base class for tied handles. Thread Perl thread creation, manipulation, and support. attrs Set subroutine attributes. fields Compile-time class fields. re Various pragmata to control behavior of regular expressions. CCCChhhhaaaannnnggggeeeessss iiiinnnn eeeexxxxiiiissssttttiiiinnnngggg mmmmoooodddduuuulllleeeessss CGI CGI has been updated to version 2.42. POSIX POSIX now has its own platform-specific hints files. Page 12 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) DB_File DB_File supports version 2.x of Berkeley DB. See ext/DB_File/Changes. MakeMaker MakeMaker now supports writing empty makefiles, provides a way to specify that site _u_m_a_s_k() policy should be honored. There is also better support for manipulation of .packlist files, and getting information about installed modules. Extensions that have both architecture-dependent and architecture-independent files are now always installed completely in the architecture-dependent locations. Previously, the shareable parts were shared both across architectures and across perl versions and were therefore liable to be overwritten with newer versions that might have subtle incompatibilities. CPAN See <perlmodinstall> and the _C_P_A_N manpage. Cwd Cwd::cwd is faster on most platforms. Benchmark Keeps better time. UUUUttttiiiilllliiiittttyyyy CCCChhhhaaaannnnggggeeeessss h2ph and related utilities have been vastly overhauled. perlcc, a new experimental front end for the compiler is available. The crude GNU configure emulator is now called configure.gnu to avoid trampling on Configure under case-insensitive filesystems. perldoc used to be rather slow. The slower features are now optional. In particular, case-insensitive searches need the -i switch, and recursive searches need -r. You can set these switches in the PERLDOC environment variable to get the old behavior. DDDDooooccccuuuummmmeeeennnnttttaaaattttiiiioooonnnn CCCChhhhaaaannnnggggeeeessss Config.pm now has a glossary of variables. _P_o_r_t_i_n_g/_p_a_t_c_h_i_n_g._p_o_d has detailed instructions on how to create and submit patches for perl. the _p_e_r_l_p_o_r_t manpage specifies guidelines on how to write portably. the _p_e_r_l_m_o_d_i_n_s_t_a_l_l manpage describes how to fetch and Page 13 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) install modules from CPAN sites. Some more Perl traps are documented now. See the _p_e_r_l_t_r_a_p manpage. NNNNeeeewwww DDDDiiiiaaaaggggnnnnoooossssttttiiiiccccssss Ambiguous call resolved as CORE::%s(), qualify as such or use & (W) A subroutine you have declared has the same name as a Perl keyword, and you have used the name without qualification for calling one or the other. Perl decided to call the builtin because the subroutine is not imported. To force interpretation as a subroutine call, either put an ampersand before the subroutine name, or qualify the name with its package. Alternatively, you can import the subroutine (or pretend that it's imported with the use subs pragma). To silently interpret it as the Perl operator, use the CORE:: prefix on the operator (e.g. CORE::log($x)) or by declaring the subroutine to be an object method (see the _a_t_t_r_s manpage). Bad index while coercing array into hash (F) The index looked up in the hash found as the 0'th element of a pseudo-hash is not legal. Index values must be at 1 or greater. See the _p_e_r_l_r_e_f manpage. Bareword "%s" refers to nonexistent package (W) You used a qualified bareword of the form Foo::, but the compiler saw no other uses of that namespace before that point. Perhaps you need to predeclare a package? Can't call method "%s" on an undefined value (F) You used the syntax of a method call, but the slot filled by the object reference or package name contains an undefined value. Something like this will reproduce the error: $BADREF = 42; process $BADREF 1,2,3; $BADREF->process(1,2,3); Can't coerce array into hash (F) You used an array where a hash was expected, but the array has no information on how to map from keys to array indices. You can do that only with arrays that have a hash reference at index 0. Page 14 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) Can't goto subroutine from an eval-string (F) The "goto subroutine" call can't be used to jump out of an eval "string". (You can use it to jump out of an eval {BLOCK}, but you probably don't want to.) Can't localize pseudo-hash element (F) You said something like local $ar->{'key'}, where $ar is a reference to a pseudo-hash. That hasn't been implemented yet, but you can get a similar effect by localizing the corresponding array element directly -- local $ar->[$ar->[0]{'key'}]. Can't use %%! because Errno.pm is not available (F) The first time the %! hash is used, perl automatically loads the Errno.pm module. The Errno module is expected to tie the %! hash to provide symbolic names for $! errno values. Cannot find an opnumber for "%s" (F) A string of a form CORE::word was given to _p_r_o_t_o_t_y_p_e(), but there is no builtin with the name word. Character class syntax [. .] is reserved for future extensions (W) Within regular expression character classes ([]) the syntax beginning with "[." and ending with ".]" is reserved for future extensions. If you need to represent those character sequences inside a regular expression character class, just quote the square brackets with the backslash: "\[." and ".\]". Character class syntax [: :] is reserved for future extensions (W) Within regular expression character classes ([]) the syntax beginning with "[:" and ending with ":]" is reserved for future extensions. If you need to represent those character sequences inside a regular expression character class, just quote the square brackets with the backslash: "\[:" and ":\]". Character class syntax [= =] is reserved for future extensions (W) Within regular expression character classes ([]) the syntax beginning with "[=" and ending with "=]" is reserved for future extensions. If you need to represent those character sequences inside a regular expression character class, just quote the square brackets with the backslash: "\[=" and "=\]". %s: Eval-group in insecure regular expression (F) Perl detected tainted data when trying to compile a regular expression that contains the (?{ ... }) zero- width assertion, which is unsafe. See the section on (?{ _c_o_d_e }) in the _p_e_r_l_r_e manpage, and the _p_e_r_l_s_e_c Page 15 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) manpage. %s: Eval-group not allowed, use re 'eval' (F) A regular expression contained the (?{ ... }) zero-width assertion, but that construct is only allowed when the use re 'eval' pragma is in effect. See the section on (?{ _c_o_d_e }) in the _p_e_r_l_r_e manpage. %s: Eval-group not allowed at run time (F) Perl tried to compile a regular expression containing the (?{ ... }) zero-width assertion at run time, as it would when the pattern contains interpolated values. Since that is a security risk, it is not allowed. If you insist, you may still do this by explicitly building the pattern from an interpolated string at run time and using that in an _e_v_a_l(). See the section on (?{ _c_o_d_e }) in the _p_e_r_l_r_e manpage. Explicit blessing to '' (assuming package main) (W) You are blessing a reference to a zero length string. This has the effect of blessing the reference into the package main. This is usually not what you want. Consider providing a default target package, e.g. _b_l_e_s_s($ref, $p or 'MyPackage'); Illegal hex digit ignored (W) You may have tried to use a character other than 0 - 9 or A - F in a hexadecimal number. Interpretation of the hexadecimal number stopped before the illegal character. No such array field (F) You tried to access an array as a hash, but the field name used is not defined. The hash at index 0 should map all valid field names to array indices for that to work. No such field "%s" in variable %s of type %s (F) You tried to access a field of a typed variable where the type does not know about the field name. The field names are looked up in the %FIELDS hash in the type package at compile time. The %FIELDS hash is usually set up with the 'fields' pragma. Out of memory during ridiculously large request (F) You can't allocate more than 2^31+"small amount" bytes. This error is most likely to be caused by a typo in the Perl program. e.g., $arr[time] instead of $arr[$time]. Range iterator outside integer range (F) One (or both) of the numeric arguments to the range Page 16 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) operator ".." are outside the range which can be represented by integers internally. One possible workaround is to force Perl to use magical string increment by prepending "0" to your numbers. package '%s' Recursive inheritance detected while looking for method '%s' in (F) More than 100 levels of inheritance were encountered while invoking a method. Probably indicates an unintended loop in your inheritance hierarchy. Reference found where even-sized list expected (W) You gave a single reference where Perl was expecting a list with an even number of elements (for assignment to a hash). This usually means that you used the anon hash constructor when you meant to use parens. In any case, a hash requires key/value ppppaaaaiiiirrrrssss. %hash = { one => 1, two => 2, }; # WRONG %hash = [ qw/ an anon array / ]; # WRONG %hash = ( one => 1, two => 2, ); # right %hash = qw( one 1 two 2 ); # also fine Undefined value assigned to typeglob (W) An undefined value was assigned to a typeglob, a la *foo = undef. This does nothing. It's possible that you really mean undef *foo. Use of reserved word "%s" is deprecated (D) The indicated bareword is a reserved word. Future versions of perl may use it as a keyword, so you're better off either explicitly quoting the word in a manner appropriate for its context of use, or using a different name altogether. The warning can be suppressed for subroutine names by either adding a & prefix, or using a package qualifier, e.g. &our(), or Foo::our(). perl: warning: Setting locale failed. (S) The whole warning message will look something like: perl: warning: Setting locale failed. perl: warning: Please check that your locale settings: LC_ALL = "En_US", LANG = (unset) are supported and installed on your system. perl: warning: Falling back to the standard locale ("C"). Exactly what were the failed locale settings varies. In the above the settings were that the LC_ALL was Page 17 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) "En_US" and the LANG had no value. This error means that Perl detected that you and/or your system administrator have set up the so-called variable system but Perl could not use those settings. This was not dead serious, fortunately: there is a "default locale" called "C" that Perl can and will use, the script will be run. Before you really fix the problem, however, you will get the same error message each time you run Perl. How to really fix the problem can be found in the _p_e_r_l_l_o_c_a_l_e manpage section LLLLOOOOCCCCAAAALLLLEEEE PPPPRRRROOOOBBBBLLLLEEEEMMMMSSSS. OOOObbbbssssoooolllleeeetttteeee DDDDiiiiaaaaggggnnnnoooossssttttiiiiccccssss Can't mktemp() (F) The _m_k_t_e_m_p() routine failed for some reason while trying to process a ----eeee switch. Maybe your /tmp partition is full, or clobbered. Can't write to temp file for ----eeee: %s (F) The write routine failed for some reason while trying to process a ----eeee switch. Maybe your /tmp partition is full, or clobbered. Cannot open temporary file (F) The create routine failed for some reason while trying to process a ----eeee switch. Maybe your /tmp partition is full, or clobbered. BBBBUUUUGGGGSSSS If you find what you think is a bug, you might check the headers of recently posted articles in the comp.lang.perl.misc newsgroup. There may also be information at http://www.perl.com/perl/, the Perl Home Page. If you believe you have an unreported bug, please run the ppppeeeerrrrllllbbbbuuuugggg program included with your release. Make sure you trim your bug down to a tiny but sufficient test case. Your bug report, along with the output of perl -V, will be sent off to <_p_e_r_l_b_u_g@_p_e_r_l._c_o_m> to be analysed by the Perl porting team. SSSSEEEEEEEE AAAALLLLSSSSOOOO The _C_h_a_n_g_e_s file for exhaustive details on what changed. The _I_N_S_T_A_L_L file for how to build Perl. The _R_E_A_D_M_E file for general stuff. The _A_r_t_i_s_t_i_c and _C_o_p_y_i_n_g files for copyright information. HHHHIIIISSSSTTTTOOOORRRRYYYY Written by Gurusamy Sarathy <_g_s_a_r@_u_m_i_c_h._e_d_u>, with many Page 18 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) contributions from The Perl Porters. Send omissions or corrections to <_p_e_r_l_b_u_g@_p_e_r_l._c_o_m>. Page 19 (printed 10/23/98) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) 1111////AAAAuuuugggg////99998888 ((((ppppeeeerrrrllll 5555....000000005555,,,, ppppaaaattttcccchhhh 00002222)))) PPPPEEEERRRRLLLLDDDDEEEELLLLTTTTAAAA((((1111)))) Page 20 (printed 10/23/98)