Perl-compatible Regular Expressions (PCRE)
The HTML documentation for PCRE comprises the following pages:
pcre.htmlpcre     
  Introductory page pcreapi.htmlpcreapi     
  PCRE's native API pcrebuild.htmlpcrebuild     
  Options for building PCRE pcrecallout.htmlpcrecallout     
  The callout facility pcrecompat.htmlpcrecompat     
  Compability with Perl pcrecpp.htmlpcrecpp     
  The C++ wrapper for the PCRE library pcregrep.htmlpcregrep     
  The pcregrep command pcrematching.htmlpcrematching     
  Discussion of the two matching algorithms pcrepartial.htmlpcrepartial     
  Using PCRE for partial matching pcrepattern.htmlpcrepattern     
  Specification of the regular expressions supported by PCRE pcreperform.htmlpcreperform     
  Some comments on performance pcreposix.htmlpcreposix     
  The POSIX API to the PCRE library pcreprecompile.htmlpcreprecompile     
  How to save and re-use compiled patterns pcresample.htmlpcresample     
  Description of the sample program pcretest.htmlpcretest     
  The pcretest command for testing PCRE There are also individual pages that summarize the interface for each function
in the library:
pcre_compile.htmlpcre_compile     
  Compile a regular expression pcre_compile2.htmlpcre_compile2     
  Compile a regular expression (alternate interface) pcre_config.htmlpcre_config     
  Show build-time configuration options pcre_copy_named_substring.htmlpcre_copy_named_substring     
  Extract named substring into given buffer pcre_copy_substring.htmlpcre_copy_substring     
  Extract numbered substring into given buffer pcre_dfa_exec.htmlpcre_dfa_exec     
  Match a compiled pattern to a subject string
    (DFA algorithm; 
not Perl compatible) pcre_exec.htmlpcre_exec     
  Match a compiled pattern to a subject string
    (Perl compatible)
pcre_free_substring.htmlpcre_free_substring     
  Free extracted substring pcre_free_substring_list.htmlpcre_free_substring_list     
  Free list of extracted substrings pcre_fullinfo.htmlpcre_fullinfo     
  Extract information about a pattern pcre_get_named_substring.htmlpcre_get_named_substring     
  Extract named substring into new memory pcre_get_stringnumber.htmlpcre_get_stringnumber     
  Convert captured string name to number pcre_get_substring.htmlpcre_get_substring     
  Extract numbered substring into new memory pcre_get_substring_list.htmlpcre_get_substring_list     
  Extract all substrings into new memory pcre_info.htmlpcre_info     
  Obsolete information extraction function pcre_maketables.htmlpcre_maketables     
  Build character tables in current locale pcre_study.htmlpcre_study     
  Study a compiled pattern pcre_version.htmlpcre_version     
  Return PCRE version and release date 