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version 1.1.1.3, 2012/10/09 09:19:17 version 1.1.1.4, 2013/07/22 08:25:56
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.TH PCREPRECOMPILE 3 "10 January 2012" "PCRE 8.30".TH PCREPRECOMPILE 3 "24 June 2012" "PCRE 8.30"
 .SH NAME  .SH NAME
 PCRE - Perl-compatible regular expressions  PCRE - Perl-compatible regular expressions
 .SH "SAVING AND RE-USING PRECOMPILED PCRE PATTERNS"  .SH "SAVING AND RE-USING PRECOMPILED PCRE PATTERNS"
Line 18  JIT data. Line 18  JIT data.
 .P  .P
 If you save compiled patterns to a file, you can copy them to a different host  If you save compiled patterns to a file, you can copy them to a different host
 and run them there. If the two hosts have different endianness (byte order),  and run them there. If the two hosts have different endianness (byte order),
you should run the \fBpcre[16]_pattern_to_host_byte_order()\fP function on theyou should run the \fBpcre[16|32]_pattern_to_host_byte_order()\fP function on the
 new host before trying to match the pattern. The matching functions return  new host before trying to match the pattern. The matching functions return
 PCRE_ERROR_BADENDIANNESS if they detect a pattern with the wrong endianness.  PCRE_ERROR_BADENDIANNESS if they detect a pattern with the wrong endianness.
 .P  .P
Line 30  restoring a compiled pattern loses any JIT optimizatio Line 30  restoring a compiled pattern loses any JIT optimizatio
 .SH "SAVING A COMPILED PATTERN"  .SH "SAVING A COMPILED PATTERN"
 .rs  .rs
 .sp  .sp
The value returned by \fBpcre[16]_compile()\fP points to a single block ofThe value returned by \fBpcre[16|32]_compile()\fP points to a single block of
 memory that holds the compiled pattern and associated data. You can find the  memory that holds the compiled pattern and associated data. You can find the
length of this block in bytes by calling \fBpcre[16]_fullinfo()\fP with anlength of this block in bytes by calling \fBpcre[16|32]_fullinfo()\fP with an
 argument of PCRE_INFO_SIZE. You can then save the data in any appropriate  argument of PCRE_INFO_SIZE. You can then save the data in any appropriate
 manner. Here is sample code for the 8-bit library that compiles a pattern and  manner. Here is sample code for the 8-bit library that compiles a pattern and
 writes it to a file. It assumes that the variable \fIfd\fP refers to a file  writes it to a file. It assumes that the variable \fIfd\fP refers to a file
Line 68  If the pattern has been studied, it is also possible t Line 68  If the pattern has been studied, it is also possible t
 data in a similar way to the compiled pattern itself. However, if the  data in a similar way to the compiled pattern itself. However, if the
 PCRE_STUDY_JIT_COMPILE was used, the just-in-time data that is created cannot  PCRE_STUDY_JIT_COMPILE was used, the just-in-time data that is created cannot
 be saved because it is too dependent on the current environment. When studying  be saved because it is too dependent on the current environment. When studying
generates additional information, \fBpcre[16]_study()\fP returns a pointer to agenerates additional information, \fBpcre[16|32]_study()\fP returns a pointer to a
\fBpcre[16]_extra\fP data block. Its format is defined in the\fBpcre[16|32]_extra\fP data block. Its format is defined in the
 .\" HTML <a href="pcreapi.html#extradata">  .\" HTML <a href="pcreapi.html#extradata">
 .\" </a>  .\" </a>
 section on matching a pattern  section on matching a pattern
Line 79  in the Line 79  in the
 \fBpcreapi\fP  \fBpcreapi\fP
 .\"  .\"
 documentation. The \fIstudy_data\fP field points to the binary study data, and  documentation. The \fIstudy_data\fP field points to the binary study data, and
this is what you must save (not the \fBpcre[16]_extra\fP block itself). Thethis is what you must save (not the \fBpcre[16|32]_extra\fP block itself). The
length of the study data can be obtained by calling \fBpcre[16]_fullinfo()\fPlength of the study data can be obtained by calling \fBpcre[16|32]_fullinfo()\fP
 with an argument of PCRE_INFO_STUDYSIZE. Remember to check that  with an argument of PCRE_INFO_STUDYSIZE. Remember to check that
\fBpcre[16]_study()\fP did return a non-NULL value before trying to save the\fBpcre[16|32]_study()\fP did return a non-NULL value before trying to save the
 study data.  study data.
 .  .
 .  .
Line 90  study data. Line 90  study data.
 .rs  .rs
 .sp  .sp
 Re-using a precompiled pattern is straightforward. Having reloaded it into main  Re-using a precompiled pattern is straightforward. Having reloaded it into main
memory, called \fBpcre[16]_pattern_to_host_byte_order()\fP if necessary,memory, called \fBpcre[16|32]_pattern_to_host_byte_order()\fP if necessary,
you pass its pointer to \fBpcre[16]_exec()\fP or \fBpcre[16]_dfa_exec()\fP inyou pass its pointer to \fBpcre[16|32]_exec()\fP or \fBpcre[16|32]_dfa_exec()\fP in
 the usual way.  the usual way.
 .P  .P
 However, if you passed a pointer to custom character tables when the pattern  However, if you passed a pointer to custom character tables when the pattern
was compiled (the \fItableptr\fP argument of \fBpcre[16]_compile()\fP), youwas compiled (the \fItableptr\fP argument of \fBpcre[16|32]_compile()\fP), you
must now pass a similar pointer to \fBpcre[16]_exec()\fP ormust now pass a similar pointer to \fBpcre[16|32]_exec()\fP or
\fBpcre[16]_dfa_exec()\fP, because the value saved with the compiled pattern\fBpcre[16|32]_dfa_exec()\fP, because the value saved with the compiled pattern
will obviously be nonsense. A field in a \fBpcre[16]_extra()\fP block is usedwill obviously be nonsense. A field in a \fBpcre[16|32]_extra()\fP block is used
 to pass this data, as described in the  to pass this data, as described in the
 .\" HTML <a href="pcreapi.html#extradata">  .\" HTML <a href="pcreapi.html#extradata">
 .\" </a>  .\" </a>
Line 116  functions to use PCRE's internal tables. Thus, you do  Line 116  functions to use PCRE's internal tables. Thus, you do 
 special action at run time in this case.  special action at run time in this case.
 .P  .P
 If you saved study data with the compiled pattern, you need to create your own  If you saved study data with the compiled pattern, you need to create your own
\fBpcre[16]_extra\fP data block and set the \fIstudy_data\fP field to point to the\fBpcre[16|32]_extra\fP data block and set the \fIstudy_data\fP field to point to the
 reloaded study data. You must also set the PCRE_EXTRA_STUDY_DATA bit in the  reloaded study data. You must also set the PCRE_EXTRA_STUDY_DATA bit in the
 \fIflags\fP field to indicate that study data is present. Then pass the  \fIflags\fP field to indicate that study data is present. Then pass the
\fBpcre[16]_extra\fP block to the matching function in the usual way. If the\fBpcre[16|32]_extra\fP block to the matching function in the usual way. If the
 pattern was studied for just-in-time optimization, that data cannot be saved,  pattern was studied for just-in-time optimization, that data cannot be saved,
 and so is lost by a save/restore cycle.  and so is lost by a save/restore cycle.
 .  .
Line 146  Cambridge CB2 3QH, England. Line 146  Cambridge CB2 3QH, England.
 .rs  .rs
 .sp  .sp
 .nf  .nf
Last updated: 10 January 2012Last updated: 24 June 2012
 Copyright (c) 1997-2012 University of Cambridge.  Copyright (c) 1997-2012 University of Cambridge.
 .fi  .fi
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changed lines
  Added in v.1.1.1.4

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