pcre2

PCRE2TEST(1) General Commands Manual PCRE2TEST(1) NAME pcre2test - a program for testing Perl-compatible regular expressions. SYNOPSIS pcre2test [options] [input file [output file]] pcre2test is a test program for the PCRE2 regular expression libraries, but it can also be used for experimenting with regular expressions. This document describes the features of the test program; for details of the regular expressions themselves, see the pcre2pattern documenta- tion. For details of the PCRE2 library function calls and their op- tions, see the pcre2api documentation. The input for pcre2test is a sequence of regular expression patterns and subject strings to be matched. There are also command lines for setting defaults and controlling some special actions. The output shows the result of each match attempt. Modifiers on external or internal command lines, the patterns, and the subject lines specify PCRE2 func- tion options, control how the subject is processed, and what output is produced. As the original fairly simple PCRE library evolved, it acquired many different features, and as a result, the original pcretest program ended up with a lot of options in a messy, arcane syntax for testing all the features. The move to the new PCRE2 API provided an opportunity to re-implement the test program as pcre2test, with a cleaner modifier syntax. Nevertheless, there are still many obscure modifiers, some of which are specifically designed for use in conjunction with the test script and data files that are distributed as part of PCRE2. All the modifiers are documented here, some without much justification, but many of them are unlikely to be of use except when testing the li- braries. PCRE2's 8-BIT, 16-BIT AND 32-BIT LIBRARIES Different versions of the PCRE2 library can be built to support charac- ter strings that are encoded in 8-bit, 16-bit, or 32-bit code units. One, two, or all three of these libraries may be simultaneously in- stalled. The pcre2test program can be used to test all the libraries. However, its own input and output are always in 8-bit format. When testing the 16-bit or 32-bit libraries, patterns and subject strings are converted to 16-bit or 32-bit format before being passed to the li- brary functions. Results are converted back to 8-bit code units for output. In the rest of this document, the names of library functions and struc- tures are given in generic form, for example, pcre_compile(). The ac- tual names used in the libraries have a suffix _8, _16, or _32, as ap- propriate. INPUT ENCODING Input to pcre2test is processed line by line, either by calling the C library's fgets() function, or via the libreadline library. In some Windows environments character 26 (hex 1A) causes an immediate end of file, and no further data is read, so this character should be avoided unless you really want that action. The input is processed using using C's string functions, so must not contain binary zeros, even though in Unix-like environments, fgets() treats any bytes other than newline as data characters. An error is generated if a binary zero is encountered. By default subject lines are processed for backslash escapes, which makes it possible to include any data value in strings that are passed to the library for matching. For patterns, there is a facility for specifying some or all of the 8-bit input characters as hexadecimal pairs, which makes it possible to in- clude binary zeros. Input for the 16-bit and 32-bit libraries When testing the 16-bit or 32-bit libraries, there is a need to be able to generate character code points greater than 255 in the strings that are passed to the library. For subject lines, backslash escapes can be used. In addition, when the utf modifier (see "Setting compilation op- tions" below) is set, the pattern and any following subject lines are interpreted as UTF-8 strings and translated to UTF-16 or UTF-32 as ap- propriate. For non-UTF testing of wide characters, the utf8_input modifier can be used. This is mutually exclusive with utf, and is allowed only in 16-bit or 32-bit mode. It causes the pattern and following subject lines to be treated as UTF-8 according to the original definition (RFC 2279), which allows for character values up to 0x7fffffff. Each charac- ter is placed in one 16-bit or 32-bit code unit (in the 16-bit case, values greater than 0xffff cause an error to occur). UTF-8 (in its original definition) is not capable of encoding values greater than 0x7fffffff, but such values can be handled by the 32-bit library. When testing this library in non-UTF mode with utf8_input set, if any character is preceded by the byte 0xff (which is an invalid byte in UTF-8) 0x80000000 is added to the character's value. This is the only way of passing such code points in a pattern string. For subject strings, using an escape sequence is preferable. COMMAND LINE OPTIONS -8 If the 8-bit library has been built, this option causes it to be used (this is the default). If the 8-bit library has not been built, this option causes an error. -16 If the 16-bit library has been built, this option causes it to be used. If only the 16-bit library has been built, this is the default. If the 16-bit library has not been built, this option causes an error. -32 If the 32-bit library has been built, this option causes it to be used. If only the 32-bit library has been built, this is the default. If the 32-bit library has not been built, this option causes an error. -ac Behave as if each pattern has the auto_callout modifier, that is, insert automatic callouts into every pattern that is com- piled. -AC As for -ac, but in addition behave as if each subject line has the callout_extra modifier, that is, show additional in- formation from callouts. -b Behave as if each pattern has the fullbincode modifier; the full internal binary form of the pattern is output after com- pilation. -C Output the version number of the PCRE2 library, and all available information about the optional features that are included, and then exit with zero exit code. All other op- tions are ignored. If both -C and -LM are present, whichever is first is recognized. -C option Output information about a specific build-time option, then exit. This functionality is intended for use in scripts such as RunTest. The following options output the value and set the exit code as indicated: ebcdic-nl the code for LF (= NL) in an EBCDIC environment: 0x15 or 0x25 0 if used in an ASCII environment exit code is always 0 linksize the configured internal link size (2, 3, or 4) exit code is set to the link size newline the default newline setting: CR, LF, CRLF, ANYCRLF, ANY, or NUL exit code is always 0 bsr the default setting for what \R matches: ANYCRLF or ANY exit code is always 0 The following options output 1 for true or 0 for false, and set the exit code to the same value: backslash-C \C is supported (not locked out) ebcdic compiled for an EBCDIC environment jit just-in-time support is available pcre2-16 the 16-bit library was built pcre2-32 the 32-bit library was built pcre2-8 the 8-bit library was built unicode Unicode support is available If an unknown option is given, an error message is output; the exit code is 0. -d Behave as if each pattern has the debug modifier; the inter- nal form and information about the compiled pattern is output after compilation; -d is equivalent to -b -i. -dfa Behave as if each subject line has the dfa modifier; matching is done using the pcre2_dfa_match() function instead of the default pcre2_match(). -error number[,number,...] Call pcre2_get_error_message() for each of the error numbers in the comma-separated list, display the resulting messages on the standard output, then exit with zero exit code. The numbers may be positive or negative. This is a convenience facility for PCRE2 maintainers. -help Output a brief summary these options and then exit. -i Behave as if each pattern has the info modifier; information about the compiled pattern is given after compilation. -jit Behave as if each pattern line has the jit modifier; after successful compilation, each pattern is passed to the just- in-time compiler, if available. -jitfast Behave as if each pattern line has the jitfast modifier; af- ter successful compilation, each pattern is passed to the just-in-time compiler, if available, and each subject line is passed directly to the JIT matcher via its "fast path". -jitverify Behave as if each pattern line has the jitverify modifier; after successful compilation, each pattern is passed to the just-in-time compiler, if available, and the use of JIT for matching is verified. -LM List modifiers: write a list of available pattern and subject modifiers to the standard output, then exit with zero exit code. All other options are ignored. If both -C and -LM are present, whichever is first is recognized. -pattern modifier-list Behave as if each pattern line contains the given modifiers. -q Do not output the version number of pcre2test at the start of execution. -S size On Unix-like systems, set the size of the run-time stack to size mebibytes (units of 1024*1024 bytes). -subject modifier-list Behave as if each subject line contains the given modifiers. -t Run each compile and match many times with a timer, and out- put the resulting times per compile or match. When JIT is used, separate times are given for the initial compile and the JIT compile. You can control the number of iterations that are used for timing by following -t with a number (as a separate item on the command line). For example, "-t 1000" iterates 1000 times. The default is to iterate 500,000 times. -tm This is like -t except that it times only the matching phase, not the compile phase. -T -TM These behave like -t and -tm, but in addition, at the end of a run, the total times for all compiles and matches are out- put. -version Output the PCRE2 version number and then exit. DESCRIPTION If pcre2test is given two filename arguments, it reads from the first and writes to the second. If the first name is "-", input is taken from the standard input. If pcre2test is given only one argument, it reads from that file and writes to stdout. Otherwise, it reads from stdin and writes to stdout. When pcre2test is built, a configuration option can specify that it should be linked with the libreadline or libedit library. When this is done, if the input is from a terminal, it is read using the readline() function. This provides line-editing and history facilities. The output from the -help option states whether or not readline() will be used. The program handles any number of tests, each of which consists of a set of input lines. Each set starts with a regular expression pattern, followed by any number of subject lines to be matched against that pat- tern. In between sets of test data, command lines that begin with # may appear. This file format, with some restrictions, can also be processed by the perltest.sh script that is distributed with PCRE2 as a means of checking that the behaviour of PCRE2 and Perl is the same. For a speci- fication of perltest.sh, see the comments near its beginning. See also the #perltest command below. When the input is a terminal, pcre2test prompts for each line of input, using "re>" to prompt for regular expression patterns, and "data>" to prompt for subject lines. Command lines starting with # can be entered only in response to the "re>" prompt. Each subject line is matched separately and independently. If you want to do multi-line matches, you have to use the \n escape sequence (or \r or \r\n, etc., depending on the newline setting) in a single line of input to encode the newline sequences. There is no limit on the length of subject lines; the input buffer is automatically extended if it is too small. There are replication features that makes it possible to generate long repetitive pattern or subject lines without having to supply them explicitly. An empty line or the end of the file signals the end of the subject lines for a test, at which point a new pattern or command line is ex- pected if there is still input to be read. COMMAND LINES In between sets of test data, a line that begins with # is interpreted as a command line. If the first character is followed by white space or an exclamation mark, the line is treated as a comment, and ignored. Otherwise, the following commands are recognized: #forbid_utf Subsequent patterns automatically have the PCRE2_NEVER_UTF and PCRE2_NEVER_UCP options set, which locks out the use of the PCRE2_UTF and PCRE2_UCP options and the use of (*UTF) and (*UCP) at the start of patterns. This command also forces an error if a subsequent pattern contains any occurrences of \P, \p, or \X, which are still supported when PCRE2_UTF is not set, but which require Unicode property support to be included in the library. This is a trigger guard that is used in test files to ensure that UTF or Unicode property tests are not accidentally added to files that are used when Unicode support is not included in the library. Setting PCRE2_NEVER_UTF and PCRE2_NEVER_UCP as a default can also be obtained by the use of #pattern; the difference is that #forbid_utf cannot be unset, and the automatic options are not displayed in pattern informa- tion, to avoid cluttering up test output. #load <filename> This command is used to load a set of precompiled patterns from a file, as described in the section entitled "Saving and restoring compiled patterns" below. #loadtables <filename> This command is used to load a set of binary character tables that can be accessed by the tables=3 qualifier. Such tables can be created by the pcre2_dftables program with the -b option. #newline_default [<newline-list>] When PCRE2 is built, a default newline convention can be specified. This determines which characters and/or character pairs are recognized as indicating a newline in a pattern or subject string. The default can be overridden when a pattern is compiled. The standard test files con- tain tests of various newline conventions, but the majority of the tests expect a single linefeed to be recognized as a newline by de- fault. Without special action the tests would fail when PCRE2 is com- piled with either CR or CRLF as the default newline. The #newline_default command specifies a list of newline types that are acceptable as the default. The types must be one of CR, LF, CRLF, ANY- CRLF, ANY, or NUL (in upper or lower case), for example: #newline_default LF Any anyCRLF If the default newline is in the list, this command has no effect. Oth- erwise, except when testing the POSIX API, a newline modifier that specifies the first newline convention in the list (LF in the above ex- ample) is added to any pattern that does not already have a newline modifier. If the newline list is empty, the feature is turned off. This command is present in a number of the standard test input files. When the POSIX API is being tested there is no way to override the de- fault newline convention, though it is possible to set the newline con- vention from within the pattern. A warning is given if the posix or posix_nosub modifier is used when #newline_default would set a default for the non-POSIX API. #pattern <modifier-list> This command sets a default modifier list that applies to all subse- quent patterns. Modifiers on a pattern can change these settings. #perltest This line is used in test files that can also be processed by perl- test.sh to confirm that Perl gives the same results as PCRE2. Subse- quent tests are checked for the use of pcre2test features that are in- compatible with the perltest.sh script. Patterns must use '/' as their delimiter, and only certain modifiers are supported. Comment lines, #pattern commands, and #subject commands that set or unset "mark" are recognized and acted on. The #perltest, #forbid_utf, and #newline_default commands, which are needed in the relevant pcre2test files, are silently ignored. All other command lines are ignored, but give a warning message. The #perltest command helps detect tests that are accidentally put in the wrong file or use the wrong delimiter. For more details of the perltest.sh script see the comments it contains. #pop [<modifiers>] #popcopy [<modifiers>] These commands are used to manipulate the stack of compiled patterns, as described in the section entitled "Saving and restoring compiled patterns" below. #save <filename> This command is used to save a set of compiled patterns to a file, as described in the section entitled "Saving and restoring compiled pat- terns" below. #subject <modifier-list> This command sets a default modifier list that applies to all subse- quent subject lines. Modifiers on a subject line can change these set- tings. MODIFIER SYNTAX Modifier lists are used with both pattern and subject lines. Items in a list are separated by commas followed by optional white space. Trailing whitespace in a modifier list is ignored. Some modifiers may be given for both patterns and subject lines, whereas others are valid only for one or the other. Each modifier has a long name, for example "an- chored", and some of them must be followed by an equals sign and a value, for example, "offset=12". Values cannot contain comma charac- ters, but may contain spaces. Modifiers that do not take values may be preceded by a minus sign to turn off a previous setting. A few of the more common modifiers can also be specified as single let- ters, for example "i" for "caseless". In documentation, following the Perl convention, these are written with a slash ("the /i modifier") for clarity. Abbreviated modifiers must all be concatenated in the first item of a modifier list. If the first item is not recognized as a long modifier name, it is interpreted as a sequence of these abbreviations. For example: /abc/ig,newline=cr,jit=3 This is a pattern line whose modifier list starts with two one-letter modifiers (/i and /g). The lower-case abbreviated modifiers are the same as used in Perl. PATTERN SYNTAX A pattern line must start with one of the following characters (common symbols, excluding pattern meta-characters): / ! " ' ` - = _ : ; , % & @ ~ This is interpreted as the pattern's delimiter. A regular expression may be continued over several input lines, in which case the newline characters are included within it. It is possible to include the delim- iter within the pattern by escaping it with a backslash, for example /abc\/def/ If you do this, the escape and the delimiter form part of the pattern, but since the delimiters are all non-alphanumeric, this does not affect its interpretation. If the terminating delimiter is immediately fol- lowed by a backslash, for example, /abc/\ then a backslash is added to the end of the pattern. This is done to provide a way of testing the error condition that arises if a pattern finishes with a backslash, because /abc\/ is interpreted as the first line of a pattern that starts with "abc/", causing pcre2test to read the next line as a continuation of the regu- lar expression. A pattern can be followed by a modifier list (details below). SUBJECT LINE SYNTAX Before each subject line is passed to pcre2_match() or pcre2_dfa_match(), leading and trailing white space is removed, and the line is scanned for backslash escapes, unless the subject_literal modi- fier was set for the pattern. The following provide a means of encoding non-printing characters in a visible way: \a alarm (BEL, \x07) \b backspace (\x08) \e escape (\x27) \f form feed (\x0c) \n newline (\x0a) \r carriage return (\x0d) \t tab (\x09) \v vertical tab (\x0b) \nnn octal character (up to 3 octal digits); always a byte unless > 255 in UTF-8 or 16-bit or 32-bit mode \o{dd...} octal character (any number of octal digits} \xhh hexadecimal byte (up to 2 hex digits) \x{hh...} hexadecimal character (any number of hex digits) The use of \x{hh...} is not dependent on the use of the utf modifier on the pattern. It is recognized always. There may be any number of hexa- decimal digits inside the braces; invalid values provoke error mes- sages. Note that \xhh specifies one byte rather than one character in UTF-8 mode; this makes it possible to construct invalid UTF-8 sequences for testing purposes. On the other hand, \x{hh} is interpreted as a UTF-8 character in UTF-8 mode, generating more than one byte if the value is greater than 127. When testing the 8-bit library not in UTF-8 mode, \x{hh} generates one byte for values less than 256, and causes an error for greater values. In UTF-16 mode, all 4-digit \x{hhhh} values are accepted. This makes it possible to construct invalid UTF-16 sequences for testing purposes. In UTF-32 mode, all 4- to 8-digit \x{...} values are accepted. This makes it possible to construct invalid UTF-32 sequences for testing purposes. There is a special backslash sequence that specifies replication of one or more characters: \[<characters>]{<count>} This makes it possible to test long strings without having to provide them as part of the file. For example: \[abc]{4} is converted to "abcabcabcabc". This feature does not support nesting. To include a closing square bracket in the characters, code it as \x5D. A backslash followed by an equals sign marks the end of the subject string and the start of a modifier list. For example: abc\=notbol,notempty If the subject string is empty and \= is followed by whitespace, the line is treated as a comment line, and is not used for matching. For example: \= This is a comment. abc\= This is an invalid modifier list. A backslash followed by any other non-alphanumeric character just es- capes that character. A backslash followed by anything else causes an error. However, if the very last character in the line is a backslash (and there is no modifier list), it is ignored. This gives a way of passing an empty line as data, since a real empty line terminates the data input. If the subject_literal modifier is set for a pattern, all subject lines that follow are treated as literals, with no special treatment of back- slashes. No replication is possible, and any subject modifiers must be set as defaults by a #subject command. PATTERN MODIFIERS There are several types of modifier that can appear in pattern lines. Except where noted below, they may also be used in #pattern commands. A pattern's modifier list can add to or override default modifiers that were set by a previous #pattern command. Setting compilation options The following modifiers set options for pcre2_compile(). Most of them set bits in the options argument of that function, but those whose names start with PCRE2_EXTRA are additional options that are set in the compile context. For the main options, there are some single-letter ab- breviations that are the same as Perl options. There is special han- dling for /x: if a second x is present, PCRE2_EXTENDED is converted into PCRE2_EXTENDED_MORE as in Perl. A third appearance adds PCRE2_EX- TENDED as well, though this makes no difference to the way pcre2_com- pile() behaves. See pcre2api for a description of the effects of these options. allow_empty_class set PCRE2_ALLOW_EMPTY_CLASS allow_surrogate_escapes set PCRE2_EXTRA_ALLOW_SURROGATE_ESCAPES alt_bsux set PCRE2_ALT_BSUX alt_circumflex set PCRE2_ALT_CIRCUMFLEX alt_verbnames set PCRE2_ALT_VERBNAMES anchored set PCRE2_ANCHORED auto_callout set PCRE2_AUTO_CALLOUT bad_escape_is_literal set PCRE2_EXTRA_BAD_ESCAPE_IS_LITERAL /i caseless set PCRE2_CASELESS dollar_endonly set PCRE2_DOLLAR_ENDONLY /s dotall set PCRE2_DOTALL dupnames set PCRE2_DUPNAMES endanchored set PCRE2_ENDANCHORED escaped_cr_is_lf set PCRE2_EXTRA_ESCAPED_CR_IS_LF /x extended set PCRE2_EXTENDED /xx extended_more set PCRE2_EXTENDED_MORE extra_alt_bsux set PCRE2_EXTRA_ALT_BSUX firstline set PCRE2_FIRSTLINE literal set PCRE2_LITERAL match_line set PCRE2_EXTRA_MATCH_LINE match_invalid_utf set PCRE2_MATCH_INVALID_UTF match_unset_backref set PCRE2_MATCH_UNSET_BACKREF match_word set PCRE2_EXTRA_MATCH_WORD /m multiline set PCRE2_MULTILINE never_backslash_c set PCRE2_NEVER_BACKSLASH_C never_ucp set PCRE2_NEVER_UCP never_utf set PCRE2_NEVER_UTF /n no_auto_capture set PCRE2_NO_AUTO_CAPTURE no_auto_possess set PCRE2_NO_AUTO_POSSESS no_dotstar_anchor set PCRE2_NO_DOTSTAR_ANCHOR no_start_optimize set PCRE2_NO_START_OPTIMIZE no_utf_check set PCRE2_NO_UTF_CHECK ucp set PCRE2_UCP ungreedy set PCRE2_UNGREEDY use_offset_limit set PCRE2_USE_OFFSET_LIMIT utf set PCRE2_UTF As well as turning on the PCRE2_UTF option, the utf modifier causes all non-printing characters in output strings to be printed using the \x{hh...} notation. Otherwise, those less than 0x100 are output in hex without the curly brackets. Setting utf in 16-bit or 32-bit mode also causes pattern and subject strings to be translated to UTF-16 or UTF-32, respectively, before being passed to library functions. Setting compilation controls The following modifiers affect the compilation process or request in- formation about the pattern. There are single-letter abbreviations for some that are heavily used in the test files. bsr=[anycrlf|unicode] specify \R handling /B bincode show binary code without lengths callout_info show callout information convert=<options> request foreign pattern conversion convert_glob_escape=c set glob escape character convert_glob_separator=c set glob separator character convert_length set convert buffer length debug same as info,fullbincode framesize show matching frame size fullbincode show binary code with lengths /I info show info about compiled pattern hex unquoted characters are hexadecimal jit[=<number>] use JIT jitfast use JIT fast path jitverify verify JIT use locale=<name> use this locale max_pattern_length=<n> set the maximum pattern length memory show memory used newline=<type> set newline type null_context compile with a NULL context parens_nest_limit=<n> set maximum parentheses depth posix use the POSIX API posix_nosub use the POSIX API with REG_NOSUB push push compiled pattern onto the stack pushcopy push a copy onto the stack stackguard=<number> test the stackguard feature subject_literal treat all subject lines as literal tables=[0|1|2|3] select internal tables use_length do not zero-terminate the pattern utf8_input treat input as UTF-8 The effects of these modifiers are described in the following sections. Newline and \R handling The bsr modifier specifies what \R in a pattern should match. If it is set to "anycrlf", \R matches CR, LF, or CRLF only. If it is set to "unicode", \R matches any Unicode newline sequence. The default can be specified when PCRE2 is built; if it is not, the default is set to Uni- code. The newline modifier specifies which characters are to be interpreted as newlines, both in the pattern and in subject lines. The type must be one of CR, LF, CRLF, ANYCRLF, ANY, or NUL (in upper or lower case). Information about a pattern The debug modifier is a shorthand for info,fullbincode, requesting all available information. The bincode modifier causes a representation of the compiled code to be output after compilation. This information does not contain length and offset values, which ensures that the same output is generated for dif- ferent internal link sizes and different code unit widths. By using bincode, the same regression tests can be used in different environ- ments. The fullbincode modifier, by contrast, does include length and offset values. This is used in a few special tests that run only for specific code unit widths and link sizes, and is also useful for one-off tests. The info modifier requests information about the compiled pattern (whether it is anchored, has a fixed first character, and so on). The information is obtained from the pcre2_pattern_info() function. Here are some typical examples: re> /(?i)(^a|^b)/m,info Capture group count = 1 Compile options: multiline Overall options: caseless multiline First code unit at start or follows newline Subject length lower bound = 1 re> /(?i)abc/info Capture group count = 0 Compile options: <none> Overall options: caseless First code unit = 'a' (caseless) Last code unit = 'c' (caseless) Subject length lower bound = 3 "Compile options" are those specified by modifiers; "overall options" have added options that are taken or deduced from the pattern. If both sets of options are the same, just a single "options" line is output; if there are no options, the line is omitted. "First code unit" is where any match must start; if there is more than one they are listed as "starting code units". "Last code unit" is the last literal code unit that must be present in any match. This is not necessarily the last character. These lines are omitted if no starting or ending code units are recorded. The subject length line is omitted when no_start_optimize is set because the minimum length is not calculated when it can never be used. The framesize modifier shows the size, in bytes, of the storage frames used by pcre2_match() for handling backtracking. The size depends on the number of capturing parentheses in the pattern. The callout_info modifier requests information about all the callouts in the pattern. A list of them is output at the end of any other infor- mation that is requested. For each callout, either its number or string is given, followed by the item that follows it in the pattern. Passing a NULL context Normally, pcre2test passes a context block to pcre2_compile(). If the null_context modifier is set, however, NULL is passed. This is for testing that pcre2_compile() behaves correctly in this case (it uses default values). Specifying pattern characters in hexadecimal The hex modifier specifies that the characters of the pattern, except for substrings enclosed in single or double quotes, are to be inter- preted as pairs of hexadecimal digits. This feature is provided as a way of creating patterns that contain binary zeros and other non-print- ing characters. White space is permitted between pairs of digits. For example, this pattern contains three characters: /ab 32 59/hex Parts of such a pattern are taken literally if quoted. This pattern contains nine characters, only two of which are specified in hexadeci- mal: /ab "literal" 32/hex Either single or double quotes may be used. There is no way of includ- ing the delimiter within a substring. The hex and expand modifiers are mutually exclusive. Specifying the pattern's length By default, patterns are passed to the compiling functions as zero-ter- minated strings but can be passed by length instead of being zero-ter- minated. The use_length modifier causes this to happen. Using a length happens automatically (whether or not use_length is set) when hex is set, because patterns specified in hexadecimal may contain binary ze- ros. If hex or use_length is used with the POSIX wrapper API (see "Using the POSIX wrapper API" below), the REG_PEND extension is used to pass the pattern's length. Specifying wide characters in 16-bit and 32-bit modes In 16-bit and 32-bit modes, all input is automatically treated as UTF-8 and translated to UTF-16 or UTF-32 when the utf modifier is set. For testing the 16-bit and 32-bit libraries in non-UTF mode, the utf8_input modifier can be used. It is mutually exclusive with utf. Input lines are interpreted as UTF-8 as a means of specifying wide characters. More details are given in "Input encoding" above. Generating long repetitive patterns Some tests use long patterns that are very repetitive. Instead of cre- ating a very long input line for such a pattern, you can use a special repetition feature, similar to the one described for subject lines above. If the expand modifier is present on a pattern, parts of the pattern that have the form \[<characters>]{<count>} are expanded before the pattern is passed to pcre2_compile(). For exam- ple, \[AB]{6000} is expanded to "ABAB..." 6000 times. This construction cannot be nested. An initial "\[" sequence is recognized only if "]{" followed by decimal digits and "}" is found later in the pattern. If not, the characters remain in the pattern unaltered. The expand and hex modifiers are mutually exclusive. If part of an expanded pattern looks like an expansion, but is really part of the actual pattern, unwanted expansion can be avoided by giving two values in the quantifier. For example, \[AB]{6000,6000} is not rec- ognized as an expansion item. If the info modifier is set on an expanded pattern, the result of the expansion is included in the information that is output. JIT compilation Just-in-time (JIT) compiling is a heavyweight optimization that can greatly speed up pattern matching. See the pcre2jit documentation for details. JIT compiling happens, optionally, after a pattern has been successfully compiled into an internal form. The JIT compiler converts this to optimized machine code. It needs to know whether the match-time options PCRE2_PARTIAL_HARD and PCRE2_PARTIAL_SOFT are going to be used, because different code is generated for the different cases. See the partial modifier in "Subject Modifiers" below for details of how these options are specified for each match attempt. JIT compilation is requested by the jit pattern modifier, which may op- tionally be followed by an equals sign and a number in the range 0 to 7. The three bits that make up the number specify which of the three JIT operating modes are to be compiled: 1 compile JIT code for non-partial matching 2 compile JIT code for soft partial matching 4 compile JIT code for hard partial matching The possible values for the jit modifier are therefore: 0 disable JIT 1 normal matching only 2 soft partial matching only 3 normal and soft partial matching 4 hard partial matching only 6 soft and hard partial matching only 7 all three modes If no number is given, 7 is assumed. The phrase "partial matching" means a call to pcre2_match() with either the PCRE2_PARTIAL_SOFT or the PCRE2_PARTIAL_HARD option set. Note that such a call may return a com- plete match; the options enable the possibility of a partial match, but do not require it. Note also that if you request JIT compilation only for partial matching (for example, jit=2) but do not set the partial modifier on a subject line, that match will not use JIT code because none was compiled for non-partial matching. If JIT compilation is successful, the compiled JIT code will automati- cally be used when an appropriate type of match is run, except when in- compatible run-time options are specified. For more details, see the pcre2jit documentation. See also the jitstack modifier below for a way of setting the size of the JIT stack. If the jitfast modifier is specified, matching is done using the JIT "fast path" interface, pcre2_jit_match(), which skips some of the san- ity checks that are done by pcre2_match(), and of course does not work when JIT is not supported. If jitfast is specified without jit, jit=7 is assumed. If the jitverify modifier is specified, information about the compiled pattern shows whether JIT compilation was or was not successful. If jitverify is specified without jit, jit=7 is assumed. If JIT compila- tion is successful when jitverify is set, the text "(JIT)" is added to the first output line after a match or non match when JIT-compiled code was actually used in the match. Setting a locale The locale modifier must specify the name of a locale, for example: /pattern/locale=fr_FR The given locale is set, pcre2_maketables() is called to build a set of character tables for the locale, and this is then passed to pcre2_com- pile() when compiling the regular expression. The same tables are used when matching the following subject lines. The locale modifier applies only to the pattern on which it appears, but can be given in a #pattern command if a default is needed. Setting a locale and alternate charac- ter tables are mutually exclusive. Showing pattern memory The memory modifier causes the size in bytes of the memory used to hold the compiled pattern to be output. This does not include the size of the pcre2_code block; it is just the actual compiled data. If the pat- tern is subsequently passed to the JIT compiler, the size of the JIT compiled code is also output. Here is an example: re> /a(b)c/jit,memory Memory allocation (code space): 21 Memory allocation (JIT code): 1910 Limiting nested parentheses The parens_nest_limit modifier sets a limit on the depth of nested parentheses in a pattern. Breaching the limit causes a compilation er- ror. The default for the library is set when PCRE2 is built, but pcre2test sets its own default of 220, which is required for running the standard test suite. Limiting the pattern length The max_pattern_length modifier sets a limit, in code units, to the length of pattern that pcre2_compile() will accept. Breaching the limit causes a compilation error. The default is the largest number a PCRE2_SIZE variable can hold (essentially unlimited). Using the POSIX wrapper API The posix and posix_nosub modifiers cause pcre2test to call PCRE2 via the POSIX wrapper API rather than its native API. When posix_nosub is used, the POSIX option REG_NOSUB is passed to regcomp(). The POSIX wrapper supports only the 8-bit library. Note that it does not imply POSIX matching semantics; for more detail see the pcre2posix documenta- tion. The following pattern modifiers set options for the regcomp() function: caseless REG_ICASE multiline REG_NEWLINE dotall REG_DOTALL ) ungreedy REG_UNGREEDY ) These options are not part of ucp REG_UCP ) the POSIX standard utf REG_UTF8 ) The regerror_buffsize modifier specifies a size for the error buffer that is passed to regerror() in the event of a compilation error. For example: /abc/posix,regerror_buffsize=20 This provides a means of testing the behaviour of regerror() when the buffer is too small for the error message. If this modifier has not been set, a large buffer is used. The aftertext and allaftertext subject modifiers work as described be- low. All other modifiers are either ignored, with a warning message, or cause an error. The pattern is passed to regcomp() as a zero-terminated string by de- fault, but if the use_length or hex modifiers are set, the REG_PEND ex- tension is used to pass it by length. Testing the stack guard feature The stackguard modifier is used to test the use of pcre2_set_com- pile_recursion_guard(), a function that is provided to enable stack availability to be checked during compilation (see the pcre2api docu- mentation for details). If the number specified by the modifier is greater than zero, pcre2_set_compile_recursion_guard() is called to set up callback from pcre2_compile() to a local function. The argument it receives is the current nesting parenthesis depth; if this is greater than the value given by the modifier, non-zero is returned, causing the compilation to be aborted. Using alternative character tables The value specified for the tables modifier must be one of the digits 0, 1, 2, or 3. It causes a specific set of built-in character tables to be passed to pcre2_compile(). This is used in the PCRE2 tests to check behaviour with different character tables. The digit specifies the ta- bles as follows: 0 do not pass any special character tables 1 the default ASCII tables, as distributed in pcre2_chartables.c.dist 2 a set of tables defining ISO 8859 characters 3 a set of tables loaded by the #loadtables command In tables 2, some characters whose codes are greater than 128 are iden- tified as letters, digits, spaces, etc. Tables 3 can be used only after a #loadtables command has loaded them from a binary file. Setting al- ternate character tables and a locale are mutually exclusive. Setting certain match controls The following modifiers are really subject modifiers, and are described under "Subject Modifiers" below. However, they may be included in a pattern's modifier list, in which case they are applied to every sub- ject line that is processed with that pattern. These modifiers do not affect the compilation process. aftertext show text after match allaftertext show text after captures allcaptures show all captures allvector show the entire ovector allusedtext show all consulted text altglobal alternative global matching /g global global matching jitstack=<n> set size of JIT stack mark show mark values replace=<string> specify a replacement string startchar show starting character when relevant substitute_callout use substitution callouts substitute_extended use PCRE2_SUBSTITUTE_EXTENDED substitute_literal use PCRE2_SUBSTITUTE_LITERAL substitute_matched use PCRE2_SUBSTITUTE_MATCHED substitute_overflow_length use PCRE2_SUBSTITUTE_OVERFLOW_LENGTH substitute_replacement_only use PCRE2_SUBSTITUTE_REPLACEMENT_ONLY substitute_skip=<n>