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Diffstat (limited to 'doc/pcre2build.3')
| -rw-r--r-- | doc/pcre2build.3 | 61 |
1 files changed, 35 insertions, 26 deletions
diff --git a/doc/pcre2build.3 b/doc/pcre2build.3 index 7586d22..540df78 100644 --- a/doc/pcre2build.3 +++ b/doc/pcre2build.3 @@ -1,4 +1,4 @@ -.TH PCRE2BUILD 3 "18 July 2017" "PCRE2 10.30" +.TH PCRE2BUILD 3 "26 April 2018" "PCRE2 10.32" .SH NAME PCRE2 - Perl-compatible regular expressions (revised API) . @@ -59,7 +59,8 @@ The following sections include descriptions of "on/off" options whose names begin with --enable or --disable. Because of the way that \fBconfigure\fP works, --enable and --disable always come in pairs, so the complementary option always exists as well, but as it specifies the default, it is not described. -Options that specify values have names that start with --with. +Options that specify values have names that start with --with. At the end of a +\fBconfigure\fP run, a summary of the configuration is output. . . .SH "BUILDING 8-BIT, 16-BIT AND 32-BIT LIBRARIES" @@ -156,8 +157,15 @@ Just-in-time (JIT) compiler support is included in the build by specifying --enable-jit .sp This support is available only for certain hardware architectures. If this -option is set for an unsupported architecture, a building error occurs. If you -are running under SELinux you may also want to add +option is set for an unsupported architecture, a building error occurs. +If in doubt, use +.sp + --enable-jit=auto +.sp +which enables JIT only if the current hardware is supported. You can check +if JIT is enabled in the configuration summary that is output at the end of a +\fBconfigure\fP run. If you are enabling JIT under SELinux you may also want to +add .sp --enable-jit-sealloc .sp @@ -208,7 +216,7 @@ separator, U+2028), and PS (paragraph separator, U+2029). The final option is .sp --enable-newline-is-nul .sp -which causes NUL (binary zero) is set as the default line-ending character. +which causes NUL (binary zero) to be set as the default line-ending character. .P Whatever default line ending convention is selected when PCRE2 is built can be overridden by applications that use the library. At build time it is @@ -236,10 +244,10 @@ Within a compiled pattern, offset values are used to point from one part to another (for example, from an opening parenthesis to an alternation metacharacter). By default, in the 8-bit and 16-bit libraries, two-byte values are used for these offsets, leading to a maximum size for a compiled pattern of -around 64K code units. This is sufficient to handle all but the most gigantic -patterns. Nevertheless, some people do want to process truly enormous patterns, -so it is possible to compile PCRE2 to use three-byte or four-byte offsets by -adding a setting such as +around 64 thousand code units. This is sufficient to handle all but the most +gigantic patterns. Nevertheless, some people do want to process truly enormous +patterns, so it is possible to compile PCRE2 to use three-byte or four-byte +offsets by adding a setting such as .sp --with-link-size=3 .sp @@ -269,12 +277,12 @@ to the \fBconfigure\fP command. This setting also applies to the \fBpcre2_dfa_match()\fP matching function, and to JIT matching (though the counting is done differently). .P -The \fBpcre2_match()\fP function starts out using a 20K vector on the system +The \fBpcre2_match()\fP function starts out using a 20KiB vector on the system stack to record backtracking points. The more nested backtracking points there are (that is, the deeper the search tree), the more memory is needed. If the initial vector is not large enough, heap memory is used, up to a certain limit, -which is specified in kilobytes. The limit can be changed at run time, as -described in the +which is specified in kibibytes (units of 1024 bytes). The limit can be changed +at run time, as described in the .\" HREF \fBpcre2api\fP .\" @@ -283,10 +291,11 @@ change this by a setting such as .sp --with-heap-limit=500 .sp -which limits the amount of heap to 500 kilobytes. This limit applies only to -interpretive matching in pcre2_match(). It does not apply when JIT (which has -its own memory arrangements) is used, nor does it apply to -\fBpcre2_dfa_match()\fP. +which limits the amount of heap to 500 KiB. This limit applies only to +interpretive matching in \fBpcre2_match()\fP and \fBpcre2_dfa_match()\fP, which +may also use the heap for internal workspace when processing complicated +patterns. This limit does not apply when JIT (which has its own memory +arrangements) is used. .P You can also explicitly limit the depth of nested backtracking in the \fBpcre2_match()\fP interpreter. This limit defaults to the value that is set @@ -394,13 +403,13 @@ they are not. .sp \fBpcre2grep\fP uses an internal buffer to hold a "window" on the file it is scanning, in order to be able to output "before" and "after" lines when it -finds a match. The starting size of the buffer is controlled by a parameter -whose default value is 20K. The buffer itself is three times this size, but -because of the way it is used for holding "before" lines, the longest line that -is guaranteed to be processable is the parameter size. If a longer line is -encountered, \fBpcre2grep\fP automatically expands the buffer, up to a -specified maximum size, whose default is 1M or the starting size, whichever is -the larger. You can change the default parameter values by adding, for example, +finds a match. The default starting size of the buffer is 20KiB. The buffer +itself is three times this size, but because of the way it is used for holding +"before" lines, the longest line that is guaranteed to be processable is the +notional buffer size. If a longer line is encountered, \fBpcre2grep\fP +automatically expands the buffer, up to a specified maximum size, whose default +is 1MiB or the starting size, whichever is the larger. You can change the +default parameter values by adding, for example, .sp --with-pcre2grep-bufsize=51200 --with-pcre2grep-max-bufsize=2097152 @@ -543,7 +552,7 @@ generated from the string. Setting --enable-fuzz-support also causes a binary called \fBpcre2fuzzcheck\fP to be created. This is normally run under valgrind or used when PCRE2 is compiled with address sanitizing enabled. It calls the fuzzing function and -outputs information about it is doing. The input strings are specified by +outputs information about what it is doing. The input strings are specified by arguments: if an argument starts with "=" the rest of it is a literal input string. Otherwise, it is assumed to be a file name, and the contents of the file are the test string. @@ -582,6 +591,6 @@ Cambridge, England. .rs .sp .nf -Last updated: 18 July 2017 -Copyright (c) 1997-2017 University of Cambridge. +Last updated: 26 April 2018 +Copyright (c) 1997-2018 University of Cambridge. .fi |