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1  News about PCRE releases  News about PCRE releases
2  ------------------------  ------------------------
3    
4    Release 6.0 07-Jun-05
5    ---------------------
6    
7    The release number has been increased to 6.0 because of the addition of several
8    major new pieces of functionality.
9    
10    A new function, pcre_dfa_exec(), which implements pattern matching using a DFA
11    algorithm, has been added. This has a number of advantages for certain cases,
12    though it does run more slowly, and lacks the ability to capture substrings. On
13    the other hand, it does find all matches, not just the first, and it works
14    better for partial matching. The pcrematching man page discusses the
15    differences.
16    
17    The pcretest program has been enhanced so that it can make use of the new
18    pcre_dfa_exec() matching function and the extra features it provides.
19    
20    The distribution now includes a C++ wrapper library. This is built
21    automatically if a C++ compiler is found. The pcrecpp man page discusses this
22    interface.
23    
24    The code itself has been re-organized into many more files, one for each
25    function, so it no longer requires everything to be linked in when static
26    linkage is used. As a consequence, some internal functions have had to have
27    their names exposed. These functions all have names starting with _pcre_. They
28    are undocumented, and are not intended for use by outside callers.
29    
30    The pcregrep program has been enhanced with new functionality such as
31    multiline-matching and options for output more matching context. See the
32    ChangeLog for a complete list of changes to the library and the utility
33    programs.
34    
35    
36    Release 5.0 13-Sep-04
37    ---------------------
38    
39    The licence under which PCRE is released has been changed to the more
40    conventional "BSD" licence.
41    
42    In the code, some bugs have been fixed, and there are also some major changes
43    in this release (which is why I've increased the number to 5.0). Some changes
44    are internal rearrangements, and some provide a number of new facilities. The
45    new features are:
46    
47    1. There's an "automatic callout" feature that inserts callouts before every
48       item in the regex, and there's a new callout field that gives the position
49       in the pattern - useful for debugging and tracing.
50    
51    2. The extra_data structure can now be used to pass in a set of character
52       tables at exec time. This is useful if compiled regex are saved and re-used
53       at a later time when the tables may not be at the same address. If the
54       default internal tables are used, the pointer saved with the compiled
55       pattern is now set to NULL, which means that you don't need to do anything
56       special unless you are using custom tables.
57    
58    3. It is possible, with some restrictions on the content of the regex, to
59       request "partial" matching. A special return code is given if all of the
60       subject string matched part of the regex. This could be useful for testing
61       an input field as it is being typed.
62    
63    4. There is now some optional support for Unicode character properties, which
64       means that the patterns items such as \p{Lu} and \X can now be used. Only
65       the general category properties are supported. If PCRE is compiled with this
66       support, an additional 90K data structure is include, which increases the
67       size of the library dramatically.
68    
69    5. There is support for saving compiled patterns and re-using them later.
70    
71    6. There is support for running regular expressions that were compiled on a
72       different host with the opposite endianness.
73    
74    7. The pcretest program has been extended to accommodate the new features.
75    
76    The main internal rearrangement is that sequences of literal characters are no
77    longer handled as strings. Instead, each character is handled on its own. This
78    makes some UTF-8 handling easier, and makes the support of partial matching
79    possible. Compiled patterns containing long literal strings will be larger as a
80    result of this change; I hope that performance will not be much affected.
81    
82    
83    Release 4.5 01-Dec-03
84    ---------------------
85    
86    Again mainly a bug-fix and tidying release, with only a couple of new features:
87    
88    1. It's possible now to compile PCRE so that it does not use recursive
89    function calls when matching. Instead it gets memory from the heap. This slows
90    things down, but may be necessary on systems with limited stacks.
91    
92    2. UTF-8 string checking has been tightened to reject overlong sequences and to
93    check that a starting offset points to the start of a character. Failure of the
94    latter returns a new error code: PCRE_ERROR_BADUTF8_OFFSET.
95    
96    3. PCRE can now be compiled for systems that use EBCDIC code.
97    
98    
99    Release 4.4 21-Aug-03
100    ---------------------
101    
102    This is mainly a bug-fix and tidying release. The only new feature is that PCRE
103    checks UTF-8 strings for validity by default. There is an option to suppress
104    this, just in case anybody wants that teeny extra bit of performance.
105    
106    
107    Releases 4.1 - 4.3
108    ------------------
109    
110    Sorry, I forgot about updating the NEWS file for these releases. Please take a
111    look at ChangeLog.
112    
113    
114  Release 4.0 17-Feb-03  Release 4.0 17-Feb-03
115  ---------------------  ---------------------
116    

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