.TH PCRETEST 1 "10 September 2012" "PCRE 8.32"

 .SH NAME

 pcretest - a program for testing Perl-compatible regular expressions.

 .SH SYNOPSIS

 .rs

 .sp

 .B pcretest "[options] [input file [output file]]"

 .sp

 \fBpcretest\fP was written as a test program for the PCRE regular expression

 library itself, 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

 .\" HREF

 \fBpcrepattern\fP

 .\"

 documentation. For details of the PCRE library function calls and their

 options, see the

 .\" HREF

 \fBpcreapi\fP

 .\"

 ,

 .\" HREF

 \fBpcre16\fP

 and

 .\" HREF

 \fBpcre32\fP

 .\"

 documentation.

 .P

 The input for \fBpcretest\fP is a sequence of regular expression patterns and

 strings to be matched, as described below. The output shows the result of each

 match. Options on the command line and the patterns control PCRE options and

 exactly what is output.

 .P

 As PCRE has evolved, it has acquired many different features, and as a result,

 \fBpcretest\fP now has rather a lot of obscure options for testing every

 possible feature. Some of these options are specifically designed for use in

 conjunction with the test script and data files that are distributed as part of

 PCRE, and are unlikely to be of use otherwise. They are all documented here,

 but without much justification.

 .

 .

 .SH "PCRE's 8-BIT, 16-BIT AND 32-BIT LIBRARIES"

 .rs

 .sp

 From release 8.30, two separate PCRE libraries can be built. The original one

 supports 8-bit character strings, whereas the newer 16-bit library supports

 character strings encoded in 16-bit units. From release 8.32, a third

 library can be built, supporting character strings encoded in 32-bit units.

 The \fBpcretest\fP program can be

 used to test all three libraries. However, it is itself still an 8-bit program,

 reading 8-bit input and writing 8-bit output. When testing the 16-bit or 32-bit

 library, the patterns and data strings are converted to 16- or 32-bit format

 before being passed to the PCRE library functions. Results are converted to

 8-bit for output.

 .P

 References to functions and structures of the form \fBpcre[16|32]_xx\fP below

 mean "\fBpcre_xx\fP when using the 8-bit library or \fBpcre16_xx\fP when using

 the 16-bit library".

 .

 .

 .SH "COMMAND LINE OPTIONS"

 .rs

 .TP 10

 \fB-8\fP

 If both the 8-bit library has been built, this option causes the 8-bit library

 to be used (which is the default); if the 8-bit library has not been built,

 this option causes an error.

 .TP 10

 \fB-16\fP

 If both the 8-bit or the 32-bit, and the 16-bit libraries have been built, this

 option causes the 16-bit library to be used. If only the 16-bit library has been

 built, this is the default (so has no effect). If only the 8-bit or the 32-bit

 library has been built, this option causes an error.

 .TP 10

 \fB-32\fP

 If both the 8-bit or the 16-bit, and the 32-bit libraries have been built, this

 option causes the 32-bit library to be used. If only the 32-bit library has been

 built, this is the default (so has no effect). If only the 8-bit or the 16-bit

 library has been built, this option causes an error.

 .TP 10

 \fB-b\fP

 Behave as if each pattern has the \fB/B\fP (show byte code) modifier; the

 internal form is output after compilation.

 .TP 10

 \fB-C\fP

 Output the version number of the PCRE library, and all available information

 about the optional features that are included, and then exit. All other options

 are ignored.

 .TP 10

 \fB-C\fP \fIoption\fP

 Output information about a specific build-time option, then exit. This

 functionality is intended for use in scripts such as \fBRunTest\fP. The

 following options output the value indicated:

 .sp

   ebcdic-nl  the code for LF (= NL) in an EBCDIC environment:

                0x15 or 0x25

                0 if used in an ASCII environment

   linksize   the internal link size (2, 3, or 4)

   newline    the default newline setting:

                CR, LF, CRLF, ANYCRLF, or ANY

 .sp

 The following options output 1 for true or zero for false:

 .sp

   ebcdic     compiled for an EBCDIC environment

   jit        just-in-time support is available

   pcre16     the 16-bit library was built

   pcre32     the 32-bit library was built

   pcre8      the 8-bit library was built

   ucp        Unicode property support is available

   utf        UTF-8 and/or UTF-16 and/or UTF-32 support is available

 .TP 10

 \fB-d\fP

 Behave as if each pattern has the \fB/D\fP (debug) modifier; the internal

 form and information about the compiled pattern is output after compilation;

 \fB-d\fP is equivalent to \fB-b -i\fP.

 .TP 10

 \fB-dfa\fP

 Behave as if each data line contains the \eD escape sequence; this causes the

 alternative matching function, \fBpcre[16|32]_dfa_exec()\fP, to be used instead

 of the standard \fBpcre[16|32]_exec()\fP function (more detail is given below).

 .TP 10

 \fB-help\fP

 Output a brief summary these options and then exit.

 .TP 10

 \fB-i\fP

 Behave as if each pattern has the \fB/I\fP modifier; information about the

 compiled pattern is given after compilation.

 .TP 10

 \fB-M\fP

 Behave as if each data line contains the \eM escape sequence; this causes

 PCRE to discover the minimum MATCH_LIMIT and MATCH_LIMIT_RECURSION settings by

 calling \fBpcre[16|32]_exec()\fP repeatedly with different limits.

 .TP 10

 \fB-m\fP

 Output the size of each compiled pattern after it has been compiled. This is

 equivalent to adding \fB/M\fP to each regular expression. The size is given in

 bytes for both libraries.

 .TP 10

 \fB-o\fP \fIosize\fP

 Set the number of elements in the output vector that is used when calling

 \fBpcre[16|32]_exec()\fP or \fBpcre[16|32]_dfa_exec()\fP to be \fIosize\fP. The

 default value is 45, which is enough for 14 capturing subexpressions for

 \fBpcre[16|32]_exec()\fP or 22 different matches for

 \fBpcre[16|32]_dfa_exec()\fP.

 The vector size can be changed for individual matching calls by including \eO

 in the data line (see below).

 .TP 10

 \fB-p\fP

 Behave as if each pattern has the \fB/P\fP modifier; the POSIX wrapper API is

 used to call PCRE. None of the other options has any effect when \fB-p\fP is

 set. This option can be used only with the 8-bit library.

 .TP 10

 \fB-q\fP

 Do not output the version number of \fBpcretest\fP at the start of execution.

 .TP 10

 \fB-S\fP \fIsize\fP

 On Unix-like systems, set the size of the run-time stack to \fIsize\fP

 megabytes.

 .TP 10

 \fB-s\fP or \fB-s+\fP

 Behave as if each pattern has the \fB/S\fP modifier; in other words, force each

 pattern to be studied. If \fB-s+\fP is used, all the JIT compile options are

 passed to \fBpcre[16|32]_study()\fP, causing just-in-time optimization to be set

 up if it is available, for both full and partial matching. Specific JIT compile

 options can be selected by following \fB-s+\fP with a digit in the range 1 to

 7, which selects the JIT compile modes as follows:

 .sp

   1  normal match only

   2  soft partial match only

   3  normal match and soft partial match

   4  hard partial match only

   6  soft and hard partial match

   7  all three modes (default)

 .sp

 If \fB-s++\fP is used instead of \fB-s+\fP (with or without a following digit),

 the text "(JIT)" is added to the first output line after a match or no match

 when JIT-compiled code was actually used.

 .sp

 Note that there are pattern options that can override \fB-s\fP, either

 specifying no studying at all, or suppressing JIT compilation.

 .sp

 If the \fB/I\fP or \fB/D\fP option is present on a pattern (requesting output

 about the compiled pattern), information about the result of studying is not

 included when studying is caused only by \fB-s\fP and neither \fB-i\fP nor

 \fB-d\fP is present on the command line. This behaviour means that the output

 from tests that are run with and without \fB-s\fP should be identical, except

 when options that output information about the actual running of a match are

 set.

 .sp

 The \fB-M\fP, \fB-t\fP, and \fB-tm\fP options, which give information about

 resources used, are likely to produce different output with and without

 \fB-s\fP. Output may also differ if the \fB/C\fP option is present on an

 individual pattern. This uses callouts to trace the the matching process, and

 this may be different between studied and non-studied patterns. If the pattern

 contains (*MARK) items there may also be differences, for the same reason. The

 \fB-s\fP command line option can be overridden for specific patterns that

 should never be studied (see the \fB/S\fP pattern modifier below).

 .TP 10

 \fB-t\fP

 Run each compile, study, and match many times with a timer, and output

 resulting time per compile or match (in milliseconds). Do not set \fB-m\fP with

 \fB-t\fP, because you will then get the size output a zillion times, and the

 timing will be distorted. You can control the number of iterations that are

 used for timing by following \fB-t\fP with a number (as a separate item on the

 command line). For example, "-t 1000" would iterate 1000 times. The default is

 to iterate 500000 times.

 .TP 10

 \fB-tm\fP

 This is like \fB-t\fP except that it times only the matching phase, not the

 compile or study phases.

 .

 .

 .SH DESCRIPTION

 .rs

 .sp

 If \fBpcretest\fP is given two filename arguments, it reads from the first and

 writes to the second. If it is given only one filename argument, it reads from

 that file and writes to stdout. Otherwise, it reads from stdin and writes to

 stdout, and prompts for each line of input, using "re>" to prompt for regular

 expressions, and "data>" to prompt for data lines.

 .P

 When \fBpcretest\fP is built, a configuration option can specify that it should

 be linked with the \fBlibreadline\fP library. When this is done, if the input

 is from a terminal, it is read using the \fBreadline()\fP function. This

 provides line-editing and history facilities. The output from the \fB-help\fP

 option states whether or not \fBreadline()\fP will be used.

 .P

 The program handles any number of sets of input on a single input file. Each

 set starts with a regular expression, and continues with any number of data

 lines to be matched against the pattern.

 .P

 Each data line is matched separately and independently. If you want to do

 multi-line matches, you have to use the \en escape sequence (or \er or \er\en,

 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 data lines; the input

 buffer is automatically extended if it is too small.

 .P

 An empty line signals the end of the data lines, at which point a new regular

 expression is read. The regular expressions are given enclosed in any

 non-alphanumeric delimiters other than backslash, for example:

 .sp

   /(a|bc)x+yz/

 .sp

 White space before the initial delimiter is ignored. 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 delimiter within the pattern

 by escaping it, for example

 .sp

   /abc\e/def/

 .sp

 If you do so, the escape and the delimiter form part of the pattern, but since

 delimiters are always non-alphanumeric, this does not affect its interpretation.

 If the terminating delimiter is immediately followed by a backslash, for

 example,

 .sp

   /abc/\e

 .sp

 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

 .sp

   /abc\e/

 .sp

 is interpreted as the first line of a pattern that starts with "abc/", causing

 pcretest to read the next line as a continuation of the regular expression.

 .

 .

 .SH "PATTERN MODIFIERS"

 .rs

 .sp

 A pattern may be followed by any number of modifiers, which are mostly single

 characters, though some of these can be qualified by further characters.

 Following Perl usage, these are referred to below as, for example, "the

 \fB/i\fP modifier", even though the delimiter of the pattern need not always be

 a slash, and no slash is used when writing modifiers. White space may appear

 between the final pattern delimiter and the first modifier, and between the

 modifiers themselves. For reference, here is a complete list of modifiers. They

 fall into several groups that are described in detail in the following

 sections.

 .sp

   \fB/8\fP              set UTF mode

   \fB/?\fP              disable UTF validity check

   \fB/+\fP              show remainder of subject after match

   \fB/=\fP              show all captures (not just those that are set)

 .sp

   \fB/A\fP              set PCRE_ANCHORED

   \fB/B\fP              show compiled code

   \fB/C\fP              set PCRE_AUTO_CALLOUT

   \fB/D\fP              same as \fB/B\fP plus \fB/I\fP

   \fB/E\fP              set PCRE_DOLLAR_ENDONLY

   \fB/F\fP              flip byte order in compiled pattern

   \fB/f\fP              set PCRE_FIRSTLINE

   \fB/G\fP              find all matches (shorten string)

   \fB/g\fP              find all matches (use startoffset)

   \fB/I\fP              show information about pattern

   \fB/i\fP              set PCRE_CASELESS

   \fB/J\fP              set PCRE_DUPNAMES

   \fB/K\fP              show backtracking control names

   \fB/L\fP              set locale

   \fB/M\fP              show compiled memory size

   \fB/m\fP              set PCRE_MULTILINE

   \fB/N\fP              set PCRE_NO_AUTO_CAPTURE

   \fB/P\fP              use the POSIX wrapper

   \fB/S\fP              study the pattern after compilation

   \fB/s\fP              set PCRE_DOTALL

   \fB/T\fP              select character tables

   \fB/U\fP              set PCRE_UNGREEDY

   \fB/W\fP              set PCRE_UCP

   \fB/X\fP              set PCRE_EXTRA

   \fB/x\fP              set PCRE_EXTENDED

   \fB/Y\fP              set PCRE_NO_START_OPTIMIZE

   \fB/Z\fP              don't show lengths in \fB/B\fP output

 .sp

   \fB/<any>\fP          set PCRE_NEWLINE_ANY

   \fB/<anycrlf>\fP      set PCRE_NEWLINE_ANYCRLF

   \fB/<cr>\fP           set PCRE_NEWLINE_CR

   \fB/<crlf>\fP         set PCRE_NEWLINE_CRLF

   \fB/<lf>\fP           set PCRE_NEWLINE_LF

   \fB/<bsr_anycrlf>\fP  set PCRE_BSR_ANYCRLF

   \fB/<bsr_unicode>\fP  set PCRE_BSR_UNICODE

   \fB/<JS>\fP           set PCRE_JAVASCRIPT_COMPAT

 .sp

 .

 .

 .SS "Perl-compatible modifiers"

 .rs

 .sp

 The \fB/i\fP, \fB/m\fP, \fB/s\fP, and \fB/x\fP modifiers set the PCRE_CASELESS,

 PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when

 \fBpcre[16|32]_compile()\fP is called. These four modifier letters have the same

 effect as they do in Perl. For example:

 .sp

   /caseless/i

 .sp

 .

 .

 .SS "Modifiers for other PCRE options"

 .rs

 .sp

 The following table shows additional modifiers for setting PCRE compile-time

 options that do not correspond to anything in Perl:

 .sp

   \fB/8\fP              PCRE_UTF8           ) when using the 8-bit

   \fB/?\fP              PCRE_NO_UTF8_CHECK  )   library

 .sp

   \fB/8\fP              PCRE_UTF16          ) when using the 16-bit

   \fB/?\fP              PCRE_NO_UTF16_CHECK )   library

 .sp

   \fB/8\fP              PCRE_UTF32          ) when using the 32-bit

   \fB/?\fP              PCRE_NO_UTF32_CHECK )   library

 .sp

   \fB/A\fP              PCRE_ANCHORED

   \fB/C\fP              PCRE_AUTO_CALLOUT

   \fB/E\fP              PCRE_DOLLAR_ENDONLY

   \fB/f\fP              PCRE_FIRSTLINE

   \fB/J\fP              PCRE_DUPNAMES

   \fB/N\fP              PCRE_NO_AUTO_CAPTURE

   \fB/U\fP              PCRE_UNGREEDY

   \fB/W\fP              PCRE_UCP

   \fB/X\fP              PCRE_EXTRA

   \fB/Y\fP              PCRE_NO_START_OPTIMIZE

   \fB/<any>\fP          PCRE_NEWLINE_ANY

   \fB/<anycrlf>\fP      PCRE_NEWLINE_ANYCRLF

   \fB/<cr>\fP           PCRE_NEWLINE_CR

   \fB/<crlf>\fP         PCRE_NEWLINE_CRLF

   \fB/<lf>\fP           PCRE_NEWLINE_LF

   \fB/<bsr_anycrlf>\fP  PCRE_BSR_ANYCRLF

   \fB/<bsr_unicode>\fP  PCRE_BSR_UNICODE

   \fB/<JS>\fP           PCRE_JAVASCRIPT_COMPAT

 .sp

 The modifiers that are enclosed in angle brackets are literal strings as shown,

 including the angle brackets, but the letters within can be in either case.

 This example sets multiline matching with CRLF as the line ending sequence:

 .sp

   /^abc/m<CRLF>

 .sp

 As well as turning on the PCRE_UTF8/16/32 option, the \fB/8\fP modifier causes

 all non-printing characters in output strings to be printed using the

 \ex{hh...} notation. Otherwise, those less than 0x100 are output in hex without

 the curly brackets.

 .P

 Full details of the PCRE options are given in the

 .\" HREF

 \fBpcreapi\fP

 .\"

 documentation.

 .

 .

 .SS "Finding all matches in a string"

 .rs

 .sp

 Searching for all possible matches within each subject string can be requested

 by the \fB/g\fP or \fB/G\fP modifier. After finding a match, PCRE is called

 again to search the remainder of the subject string. The difference between

 \fB/g\fP and \fB/G\fP is that the former uses the \fIstartoffset\fP argument to

 \fBpcre[16|32]_exec()\fP to start searching at a new point within the entire

 string (which is in effect what Perl does), whereas the latter passes over a

 shortened substring. This makes a difference to the matching process if the

 pattern begins with a lookbehind assertion (including \eb or \eB).

 .P

 If any call to \fBpcre[16|32]_exec()\fP in a \fB/g\fP or \fB/G\fP sequence matches

 an empty string, the next call is done with the PCRE_NOTEMPTY_ATSTART and

 PCRE_ANCHORED flags set in order to search for another, non-empty, match at the

 same point. If this second match fails, the start offset is advanced, and the

 normal match is retried. This imitates the way Perl handles such cases when

 using the \fB/g\fP modifier or the \fBsplit()\fP function. Normally, the start

 offset is advanced by one character, but if the newline convention recognizes

 CRLF as a newline, and the current character is CR followed by LF, an advance

 of two is used.

 .

 .

 .SS "Other modifiers"

 .rs

 .sp

 There are yet more modifiers for controlling the way \fBpcretest\fP

 operates.

 .P

 The \fB/+\fP modifier requests that as well as outputting the substring that

 matched the entire pattern, \fBpcretest\fP should in addition output the

 remainder of the subject string. This is useful for tests where the subject

 contains multiple copies of the same substring. If the \fB+\fP modifier appears

 twice, the same action is taken for captured substrings. In each case the

 remainder is output on the following line with a plus character following the

 capture number. Note that this modifier must not immediately follow the /S

 modifier because /S+ and /S++ have other meanings.

 .P

 The \fB/=\fP modifier requests that the values of all potential captured

 parentheses be output after a match. By default, only those up to the highest

 one actually used in the match are output (corresponding to the return code

 from \fBpcre[16|32]_exec()\fP). Values in the offsets vector corresponding to

 higher numbers should be set to -1, and these are output as "<unset>". This

 modifier gives a way of checking that this is happening.

 .P

 The \fB/B\fP modifier is a debugging feature. It requests that \fBpcretest\fP

 output a representation of the compiled code after compilation. Normally this

 information contains length and offset values; however, if \fB/Z\fP is also

 present, this data is replaced by spaces. This is a special feature for use in

 the automatic test scripts; it ensures that the same output is generated for

 different internal link sizes.

 .P

 The \fB/D\fP modifier is a PCRE debugging feature, and is equivalent to

 \fB/BI\fP, that is, both the \fB/B\fP and the \fB/I\fP modifiers.

 .P

 The \fB/F\fP modifier causes \fBpcretest\fP to flip the byte order of the

 2-byte and 4-byte fields in the compiled pattern. This facility is for testing

 the feature in PCRE that allows it to execute patterns that were compiled on a

 host with a different endianness. This feature is not available when the POSIX

 interface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is

 specified. See also the section about saving and reloading compiled patterns

 below.

 .P

 The \fB/I\fP modifier requests that \fBpcretest\fP output information about the

 compiled pattern (whether it is anchored, has a fixed first character, and

 so on). It does this by calling \fBpcre[16|32]_fullinfo()\fP after compiling a

 pattern. If the pattern is studied, the results of that are also output.

 .P

 The \fB/K\fP modifier requests \fBpcretest\fP to show names from backtracking

 control verbs that are returned from calls to \fBpcre[16|32]_exec()\fP. It causes

 \fBpcretest\fP to create a \fBpcre[16|32]_extra\fP block if one has not already

 been created by a call to \fBpcre[16|32]_study()\fP, and to set the

 PCRE_EXTRA_MARK flag and the \fBmark\fP field within it, every time that

 \fBpcre[16|32]_exec()\fP is called. If the variable that the \fBmark\fP field

 points to is non-NULL for a match, non-match, or partial match, \fBpcretest\fP

 prints the string to which it points. For a match, this is shown on a line by

 itself, tagged with "MK:". For a non-match it is added to the message.

 .P

 The \fB/L\fP modifier must be followed directly by the name of a locale, for

 example,

 .sp

   /pattern/Lfr_FR

 .sp

 For this reason, it must be the last modifier. The given locale is set,

 \fBpcre[16|32]_maketables()\fP is called to build a set of character tables for

 the locale, and this is then passed to \fBpcre[16|32]_compile()\fP when compiling

 the regular expression. Without an \fB/L\fP (or \fB/T\fP) modifier, NULL is

 passed as the tables pointer; that is, \fB/L\fP applies only to the expression

 on which it appears.

 .P

 The \fB/M\fP modifier causes the size in bytes of the memory block used to hold

 the compiled pattern to be output. This does not include the size of the

 \fBpcre[16|32]\fP block; it is just the actual compiled data. If the pattern is

 successfully studied with the PCRE_STUDY_JIT_COMPILE option, the size of the

 JIT compiled code is also output.

 .P

 The \fB/S\fP modifier causes \fBpcre[16|32]_study()\fP to be called after the

 expression has been compiled, and the results used when the expression is

 matched. There are a number of qualifying characters that may follow \fB/S\fP.

 They may appear in any order.

 .P

 If \fBS\fP is followed by an exclamation mark, \fBpcre[16|32]_study()\fP is called

 with the PCRE_STUDY_EXTRA_NEEDED option, causing it always to return a

 \fBpcre_extra\fP block, even when studying discovers no useful information.

 .P

 If \fB/S\fP is followed by a second S character, it suppresses studying, even

 if it was requested externally by the \fB-s\fP command line option. This makes

 it possible to specify that certain patterns are always studied, and others are

 never studied, independently of \fB-s\fP. This feature is used in the test

 files in a few cases where the output is different when the pattern is studied.

 .P

 If the \fB/S\fP modifier is followed by a + character, the call to

 \fBpcre[16|32]_study()\fP is made with all the JIT study options, requesting

 just-in-time optimization support if it is available, for both normal and

 partial matching. If you want to restrict the JIT compiling modes, you can

 follow \fB/S+\fP with a digit in the range 1 to 7:

 .sp

   1  normal match only

   2  soft partial match only

   3  normal match and soft partial match

   4  hard partial match only

   6  soft and hard partial match

   7  all three modes (default)

 .sp

 If \fB/S++\fP is used instead of \fB/S+\fP (with or without a following digit),

 the text "(JIT)" is added to the first output line after a match or no match

 when JIT-compiled code was actually used.

 .P

 Note that there is also an independent \fB/+\fP modifier; it must not be given

 immediately after \fB/S\fP or \fB/S+\fP because this will be misinterpreted.

 .P

 If JIT studying is successful, the compiled JIT code will automatically be used

 when \fBpcre[16|32]_exec()\fP is run, except when incompatible run-time options

 are specified. For more details, see the

 .\" HREF

 \fBpcrejit\fP

 .\"

 documentation. See also the \fB\eJ\fP escape sequence below for a way of

 setting the size of the JIT stack.

 .P

 Finally, if \fB/S\fP is followed by a minus character, JIT compilation is

 suppressed, even if it was requested externally by the \fB-s\fP command line

 option. This makes it possible to specify that JIT is never to be used for

 certain patterns.

 .P

 The \fB/T\fP modifier must be followed by a single digit. It causes a specific

 set of built-in character tables to be passed to \fBpcre[16|32]_compile()\fP. It

 is used in the standard PCRE tests to check behaviour with different character

 tables. The digit specifies the tables as follows:

 .sp

   0   the default ASCII tables, as distributed in

         pcre_chartables.c.dist

   1   a set of tables defining ISO 8859 characters

 .sp

 In table 1, some characters whose codes are greater than 128 are identified as

 letters, digits, spaces, etc.

 .

 .

 .SS "Using the POSIX wrapper API"

 .rs

 .sp

 The \fB/P\fP modifier causes \fBpcretest\fP to call PCRE via the POSIX wrapper

 API rather than its native API. This supports only the 8-bit library. When

 \fB/P\fP is set, the following modifiers set options for the \fBregcomp()\fP

 function:

 .sp

   /i    REG_ICASE

   /m    REG_NEWLINE

   /N    REG_NOSUB

   /s    REG_DOTALL     )

   /U    REG_UNGREEDY   ) These options are not part of

   /W    REG_UCP        )   the POSIX standard

   /8    REG_UTF8       )

 .sp

 The \fB/+\fP modifier works as described above. All other modifiers are

 ignored.

 .

 .

 .SH "DATA LINES"

 .rs

 .sp

 Before each data line is passed to \fBpcre[16|32]_exec()\fP, leading and trailing

 white space is removed, and it is then scanned for \e escapes. Some of these

 are pretty esoteric features, intended for checking out some of the more

 complicated features of PCRE. If you are just testing "ordinary" regular

 expressions, you probably don't need any of these. The following escapes are

 recognized:

 .sp

   \ea         alarm (BEL, \ex07)

   \eb         backspace (\ex08)

   \ee         escape (\ex27)

   \ef         form feed (\ex0c)

   \en         newline (\ex0a)

 .\" JOIN

   \eqdd       set the PCRE_MATCH_LIMIT limit to dd

                (any number of digits)

   \er         carriage return (\ex0d)

   \et         tab (\ex09)

   \ev         vertical tab (\ex0b)

   \ennn       octal character (up to 3 octal digits); always

                a byte unless > 255 in UTF-8 or 16-bit or 32-bit mode

   \exhh       hexadecimal byte (up to 2 hex digits)

   \ex{hh...}  hexadecimal character (any number of hex digits)

 .\" JOIN

   \eA         pass the PCRE_ANCHORED option to \fBpcre[16|32]_exec()\fP

                or \fBpcre[16|32]_dfa_exec()\fP

 .\" JOIN

   \eB         pass the PCRE_NOTBOL option to \fBpcre[16|32]_exec()\fP

                or \fBpcre[16|32]_dfa_exec()\fP

 .\" JOIN

   \eCdd       call pcre[16|32]_copy_substring() for substring dd

                after a successful match (number less than 32)

 .\" JOIN

   \eCname     call pcre[16|32]_copy_named_substring() for substring

                "name" after a successful match (name termin-

                ated by next non alphanumeric character)

 .\" JOIN

   \eC+        show the current captured substrings at callout

                time

   \eC-        do not supply a callout function

 .\" JOIN

   \eC!n       return 1 instead of 0 when callout number n is

                reached

 .\" JOIN

   \eC!n!m     return 1 instead of 0 when callout number n is

                reached for the nth time

 .\" JOIN

   \eC*n       pass the number n (may be negative) as callout

                data; this is used as the callout return value

   \eD         use the \fBpcre[16|32]_dfa_exec()\fP match function

   \eF         only shortest match for \fBpcre[16|32]_dfa_exec()\fP

 .\" JOIN

   \eGdd       call pcre[16|32]_get_substring() for substring dd

                after a successful match (number less than 32)

 .\" JOIN

   \eGname     call pcre[16|32]_get_named_substring() for substring

                "name" after a successful match (name termin-

                ated by next non-alphanumeric character)

 .\" JOIN

   \eJdd       set up a JIT stack of dd kilobytes maximum (any

                number of digits)

 .\" JOIN

   \eL         call pcre[16|32]_get_substringlist() after a

                successful match

 .\" JOIN

   \eM         discover the minimum MATCH_LIMIT and

                MATCH_LIMIT_RECURSION settings

 .\" JOIN

   \eN         pass the PCRE_NOTEMPTY option to \fBpcre[16|32]_exec()\fP

                or \fBpcre[16|32]_dfa_exec()\fP; if used twice, pass the

                PCRE_NOTEMPTY_ATSTART option

 .\" JOIN

   \eOdd       set the size of the output vector passed to

                \fBpcre[16|32]_exec()\fP to dd (any number of digits)

 .\" JOIN

   \eP         pass the PCRE_PARTIAL_SOFT option to \fBpcre[16|32]_exec()\fP

                or \fBpcre[16|32]_dfa_exec()\fP; if used twice, pass the

                PCRE_PARTIAL_HARD option

 .\" JOIN

   \eQdd       set the PCRE_MATCH_LIMIT_RECURSION limit to dd

                (any number of digits)

   \eR         pass the PCRE_DFA_RESTART option to \fBpcre[16|32]_dfa_exec()\fP

   \eS         output details of memory get/free calls during matching

 .\" JOIN

   \eY         pass the PCRE_NO_START_OPTIMIZE option to \fBpcre[16|32]_exec()\fP

                or \fBpcre[16|32]_dfa_exec()\fP

 .\" JOIN

   \eZ         pass the PCRE_NOTEOL option to \fBpcre[16|32]_exec()\fP

                or \fBpcre[16|32]_dfa_exec()\fP

 .\" JOIN

   \e?         pass the PCRE_NO_UTF[8|16|32]_CHECK option to

                \fBpcre[16|32]_exec()\fP or \fBpcre[16|32]_dfa_exec()\fP

 .\" JOIN

   \e>dd       start the match at offset dd (optional "-"; then

                any number of digits); this sets the \fIstartoffset\fP

                argument for \fBpcre[16|32]_exec()\fP or \fBpcre[16|32]_dfa_exec()\fP

 .\" JOIN

   \e<cr>      pass the PCRE_NEWLINE_CR option to \fBpcre[16|32]_exec()\fP

                or \fBpcre[16|32]_dfa_exec()\fP

 .\" JOIN

   \e<lf>      pass the PCRE_NEWLINE_LF option to \fBpcre[16|32]_exec()\fP

                or \fBpcre[16|32]_dfa_exec()\fP

 .\" JOIN

   \e<crlf>    pass the PCRE_NEWLINE_CRLF option to \fBpcre[16|32]_exec()\fP

                or \fBpcre[16|32]_dfa_exec()\fP

 .\" JOIN

   \e<anycrlf> pass the PCRE_NEWLINE_ANYCRLF option to \fBpcre[16|32]_exec()\fP

                or \fBpcre[16|32]_dfa_exec()\fP

 .\" JOIN

   \e<any>     pass the PCRE_NEWLINE_ANY option to \fBpcre[16|32]_exec()\fP

                or \fBpcre[16|32]_dfa_exec()\fP

 .sp

 The use of \ex{hh...} is not dependent on the use of the \fB/8\fP modifier on

 the pattern. It is recognized always. There may be any number of hexadecimal

 digits inside the braces; invalid values provoke error messages.

 .P

 Note that \exhh 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, \ex{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, \ex{hh} generates one byte

 for values less than 256, and causes an error for greater values.

 .P

 In UTF-16 mode, all 4-digit \ex{hhhh} values are accepted. This makes it

 possible to construct invalid UTF-16 sequences for testing purposes.

 .P

 In UTF-32 mode, all 4- to 8-digit \ex{...} values are accepted. This makes it

 possible to construct invalid UTF-32 sequences for testing purposes.

 .P

 The escapes that specify line ending sequences are literal strings, exactly as

 shown. No more than one newline setting should be present in any data line.

 .P

 A backslash followed by anything else just escapes the anything else. If

 the very last character is a backslash, it is ignored. This gives a way of

 passing an empty line as data, since a real empty line terminates the data

 input.

 .P

 The \fB\eJ\fP escape provides a way of setting the maximum stack size that is

 used by the just-in-time optimization code. It is ignored if JIT optimization

 is not being used. Providing a stack that is larger than the default 32K is

 necessary only for very complicated patterns.

 .P

 If \eM is present, \fBpcretest\fP calls \fBpcre[16|32]_exec()\fP several times,

 with different values in the \fImatch_limit\fP and \fImatch_limit_recursion\fP

 fields of the \fBpcre[16|32]_extra\fP data structure, until it finds the minimum

 numbers for each parameter that allow \fBpcre[16|32]_exec()\fP to complete without

 error. Because this is testing a specific feature of the normal interpretive

 \fBpcre[16|32]_exec()\fP execution, the use of any JIT optimization that might

 have been set up by the \fB/S+\fP qualifier of \fB-s+\fP option is disabled.

 .P

 The \fImatch_limit\fP number is a measure of the amount of backtracking

 that takes place, and checking it out can be instructive. For most simple

 matches, the number is quite small, but for patterns with very large numbers of

 matching possibilities, it can become large very quickly with increasing length

 of subject string. The \fImatch_limit_recursion\fP number is a measure of how

 much stack (or, if PCRE is compiled with NO_RECURSE, how much heap) memory is

 needed to complete the match attempt.

 .P

 When \eO is used, the value specified may be higher or lower than the size set

 by the \fB-O\fP command line option (or defaulted to 45); \eO applies only to

 the call of \fBpcre[16|32]_exec()\fP for the line in which it appears.

 .P

 If the \fB/P\fP modifier was present on the pattern, causing the POSIX wrapper

 API to be used, the only option-setting sequences that have any effect are \eB,

 \eN, and \eZ, causing REG_NOTBOL, REG_NOTEMPTY, and REG_NOTEOL, respectively,

 to be passed to \fBregexec()\fP.

 .

 .

 .SH "THE ALTERNATIVE MATCHING FUNCTION"

 .rs

 .sp

 By default, \fBpcretest\fP uses the standard PCRE matching function,

 \fBpcre[16|32]_exec()\fP to match each data line. PCRE also supports an

 alternative matching function, \fBpcre[16|32]_dfa_test()\fP, which operates in a

 different way, and has some restrictions. The differences between the two

 functions are described in the

 .\" HREF

 \fBpcrematching\fP

 .\"

 documentation.

 .P

 If a data line contains the \eD escape sequence, or if the command line

 contains the \fB-dfa\fP option, the alternative matching function is used.

 This function finds all possible matches at a given point. If, however, the \eF

 escape sequence is present in the data line, it stops after the first match is

 found. This is always the shortest possible match.

 .

 .

 .SH "DEFAULT OUTPUT FROM PCRETEST"

 .rs

 .sp

 This section describes the output when the normal matching function,

 \fBpcre[16|32]_exec()\fP, is being used.

 .P

 When a match succeeds, \fBpcretest\fP outputs the list of captured substrings

 that \fBpcre[16|32]_exec()\fP returns, starting with number 0 for the string that

 matched the whole pattern. Otherwise, it outputs "No match" when the return is

 PCRE_ERROR_NOMATCH, and "Partial match:" followed by the partially matching

 substring when \fBpcre[16|32]_exec()\fP returns PCRE_ERROR_PARTIAL. (Note that

 this is the entire substring that was inspected during the partial match; it

 may include characters before the actual match start if a lookbehind assertion,

 \eK, \eb, or \eB was involved.) For any other return, \fBpcretest\fP outputs

 the PCRE negative error number and a short descriptive phrase. If the error is

 a failed UTF string check, the offset of the start of the failing character and

 the reason code are also output, provided that the size of the output vector is

 at least two. Here is an example of an interactive \fBpcretest\fP run.

 .sp

   $ pcretest

   PCRE version 8.13 2011-04-30

 .sp

     re> /^abc(\ed+)/

   data> abc123

    0: abc123

    1: 123

   data> xyz

   No match

 .sp

 Unset capturing substrings that are not followed by one that is set are not

 returned by \fBpcre[16|32]_exec()\fP, and are not shown by \fBpcretest\fP. In the

 following example, there are two capturing substrings, but when the first data

 line is matched, the second, unset substring is not shown. An "internal" unset

 substring is shown as "<unset>", as for the second data line.

 .sp

     re> /(a)|(b)/

   data> a

    0: a

    1: a

   data> b

    0: b

    1: <unset>

    2: b

 .sp

 If the strings contain any non-printing characters, they are output as \exhh

 escapes if the value is less than 256 and UTF mode is not set. Otherwise they

 are output as \ex{hh...} escapes. See below for the definition of non-printing

 characters. If the pattern has the \fB/+\fP modifier, the output for substring

 0 is followed by the the rest of the subject string, identified by "0+" like

 this:

 .sp

     re> /cat/+

   data> cataract

    0: cat

    0+ aract

 .sp

 If the pattern has the \fB/g\fP or \fB/G\fP modifier, the results of successive

 matching attempts are output in sequence, like this:

 .sp

     re> /\eBi(\ew\ew)/g

   data> Mississippi

    0: iss

    1: ss

    0: iss

    1: ss

    0: ipp

    1: pp

 .sp

 "No match" is output only if the first match attempt fails. Here is an example

 of a failure message (the offset 4 that is specified by \e>4 is past the end of

 the subject string):

 .sp

     re> /xyz/

   data> xyz\e>4

   Error -24 (bad offset value)

 .P

 If any of the sequences \fB\eC\fP, \fB\eG\fP, or \fB\eL\fP are present in a

 data line that is successfully matched, the substrings extracted by the

 convenience functions are output with C, G, or L after the string number

 instead of a colon. This is in addition to the normal full list. The string

 length (that is, the return from the extraction function) is given in

 parentheses after each string for \fB\eC\fP and \fB\eG\fP.

 .P

 Note that whereas patterns can be continued over several lines (a plain ">"

 prompt is used for continuations), data lines may not. However newlines can be

 included in data by means of the \en escape (or \er, \er\en, etc., depending on

 the newline sequence setting).

 .

 .

 .

 .SH "OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION"

 .rs

 .sp

 When the alternative matching function, \fBpcre[16|32]_dfa_exec()\fP, is used (by

 means of the \eD escape sequence or the \fB-dfa\fP command line option), the

 output consists of a list of all the matches that start at the first point in

 the subject where there is at least one match. For example:

 .sp

     re> /(tang|tangerine|tan)/

   data> yellow tangerine\eD

    0: tangerine

    1: tang

    2: tan

 .sp

 (Using the normal matching function on this data finds only "tang".) The

 longest matching string is always given first (and numbered zero). After a

 PCRE_ERROR_PARTIAL return, the output is "Partial match:", followed by the

 partially matching substring. (Note that this is the entire substring that was

 inspected during the partial match; it may include characters before the actual

 match start if a lookbehind assertion, \eK, \eb, or \eB was involved.)

 .P

 If \fB/g\fP is present on the pattern, the search for further matches resumes

 at the end of the longest match. For example:

 .sp

     re> /(tang|tangerine|tan)/g

   data> yellow tangerine and tangy sultana\eD

    0: tangerine

    1: tang

    2: tan

    0: tang

    1: tan

    0: tan

 .sp

 Since the matching function does not support substring capture, the escape

 sequences that are concerned with captured substrings are not relevant.

 .

 .

 .SH "RESTARTING AFTER A PARTIAL MATCH"

 .rs

 .sp

 When the alternative matching function has given the PCRE_ERROR_PARTIAL return,

 indicating that the subject partially matched the pattern, you can restart the

 match with additional subject data by means of the \eR escape sequence. For

 example:

 .sp

     re> /^\ed?\ed(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\ed\ed$/

   data> 23ja\eP\eD

   Partial match: 23ja

   data> n05\eR\eD

    0: n05

 .sp

 For further information about partial matching, see the

 .\" HREF

 \fBpcrepartial\fP

 .\"

 documentation.

 .

 .

 .SH CALLOUTS

 .rs

 .sp

 If the pattern contains any callout requests, \fBpcretest\fP's callout function

 is called during matching. This works with both matching functions. By default,

 the called function displays the callout number, the start and current

 positions in the text at the callout time, and the next pattern item to be

 tested. For example:

 .sp

   --->pqrabcdef

     0    ^  ^     \ed

 .sp

 This output indicates that callout number 0 occurred for a match attempt

 starting at the fourth character of the subject string, when the pointer was at

 the seventh character of the data, and when the next pattern item was \ed. Just

 one circumflex is output if the start and current positions are the same.

 .P

 Callouts numbered 255 are assumed to be automatic callouts, inserted as a

 result of the \fB/C\fP pattern modifier. In this case, instead of showing the

 callout number, the offset in the pattern, preceded by a plus, is output. For

 example:

 .sp

     re> /\ed?[A-E]\e*/C

   data> E*

   --->E*

    +0 ^      \ed?

    +3 ^      [A-E]

    +8 ^^     \e*

   +10 ^ ^

    0: E*

 .sp

 If a pattern contains (*MARK) items, an additional line is output whenever

 a change of latest mark is passed to the callout function. For example:

 .sp

     re> /a(*MARK:X)bc/C

   data> abc

   --->abc

    +0 ^       a

    +1 ^^      (*MARK:X)

   +10 ^^      b

   Latest Mark: X

   +11 ^ ^     c

   +12 ^  ^

    0: abc

 .sp

 The mark changes between matching "a" and "b", but stays the same for the rest

 of the match, so nothing more is output. If, as a result of backtracking, the

 mark reverts to being unset, the text "<unset>" is output.

 .P

 The callout function in \fBpcretest\fP returns zero (carry on matching) by

 default, but you can use a \eC item in a data line (as described above) to

 change this and other parameters of the callout.

 .P

 Inserting callouts can be helpful when using \fBpcretest\fP to check

 complicated regular expressions. For further information about callouts, see

 the

 .\" HREF

 \fBpcrecallout\fP

 .\"

 documentation.

 .

 .

 .

 .SH "NON-PRINTING CHARACTERS"

 .rs

 .sp

 When \fBpcretest\fP is outputting text in the compiled version of a pattern,

 bytes other than 32-126 are always treated as non-printing characters are are

 therefore shown as hex escapes.

 .P

 When \fBpcretest\fP is outputting text that is a matched part of a subject

 string, it behaves in the same way, unless a different locale has been set for

 the pattern (using the \fB/L\fP modifier). In this case, the \fBisprint()\fP

 function to distinguish printing and non-printing characters.

 .

 .

 .

 .SH "SAVING AND RELOADING COMPILED PATTERNS"

 .rs

 .sp

 The facilities described in this section are not available when the POSIX

 interface to PCRE is being used, that is, when the \fB/P\fP pattern modifier is

 specified.

 .P

 When the POSIX interface is not in use, you can cause \fBpcretest\fP to write a

 compiled pattern to a file, by following the modifiers with > and a file name.

 For example:

 .sp

   /pattern/im >/some/file

 .sp

 See the

 .\" HREF

 \fBpcreprecompile\fP

 .\"

 documentation for a discussion about saving and re-using compiled patterns.

 Note that if the pattern was successfully studied with JIT optimization, the

 JIT data cannot be saved.

 .P

 The data that is written is binary. The first eight bytes are the length of the

 compiled pattern data followed by the length of the optional study data, each

 written as four bytes in big-endian order (most significant byte first). If

 there is no study data (either the pattern was not studied, or studying did not

 return any data), the second length is zero. The lengths are followed by an

 exact copy of the compiled pattern. If there is additional study data, this

 (excluding any JIT data) follows immediately after the compiled pattern. After

 writing the file, \fBpcretest\fP expects to read a new pattern.

 .P

 A saved pattern can be reloaded into \fBpcretest\fP by specifying < and a file

 name instead of a pattern. The name of the file must not contain a < character,

 as otherwise \fBpcretest\fP will interpret the line as a pattern delimited by <

 characters.

 For example:

 .sp

    re> </some/file

   Compiled pattern loaded from /some/file

   No study data

 .sp

 If the pattern was previously studied with the JIT optimization, the JIT

 information cannot be saved and restored, and so is lost. When the pattern has

 been loaded, \fBpcretest\fP proceeds to read data lines in the usual way.

 .P

 You can copy a file written by \fBpcretest\fP to a different host and reload it

 there, even if the new host has opposite endianness to the one on which the

 pattern was compiled. For example, you can compile on an i86 machine and run on

 a SPARC machine. When a pattern is reloaded on a host with different

 endianness, the confirmation message is changed to:

 .sp

   Compiled pattern (byte-inverted) loaded from /some/file

 .sp

 The test suite contains some saved pre-compiled patterns with different

 endianness. These are reloaded using "<!" instead of just "<". This suppresses

 the "(byte-inverted)" text so that the output is the same on all hosts. It also

 forces debugging output once the pattern has been reloaded.

 .P

 File names for saving and reloading can be absolute or relative, but note that

 the shell facility of expanding a file name that starts with a tilde (~) is not

 available.

 .P

 The ability to save and reload files in \fBpcretest\fP is intended for testing

 and experimentation. It is not intended for production use because only a

 single pattern can be written to a file. Furthermore, there is no facility for

 supplying custom character tables for use with a reloaded pattern. If the

 original pattern was compiled with custom tables, an attempt to match a subject

 string using a reloaded pattern is likely to cause \fBpcretest\fP to crash.

 Finally, if you attempt to load a file that is not in the correct format, the

 result is undefined.

 .

 .

 .SH "SEE ALSO"

 .rs

 .sp

 \fBpcre\fP(3), \fBpcre16\fP(3), \fBpcre32\fP(3), \fBpcreapi\fP(3),

 \fBpcrecallout\fP(3),

 \fBpcrejit\fP, \fBpcrematching\fP(3), \fBpcrepartial\fP(d),

 \fBpcrepattern\fP(3), \fBpcreprecompile\fP(3).

 .

 .

 .SH AUTHOR

 .rs

 .sp

 .nf

 Philip Hazel

 University Computing Service

 Cambridge CB2 3QH, England.

 .fi

 .

 .

 .SH REVISION

 .rs

 .sp

 .nf

 Last updated: 10 September 2012

 Copyright (c) 1997-2012 University of Cambridge.

 .fi