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::-- hoxide [<<DateTime(2005-07-30T12:48:24Z)>>]
<<TableOfContents>>
== libregex ==
=== 简介 ===
 GNU C Library 中的正则表达式库

=== 官方页面 ===

=== 文档 ===

=== 例子 ===
{{{
#!cplusplus
#include<stdio.h>
#include<stdlib.h>
#include<regex.h>

const char *p[] = { "abc" , "abc", "a.c" , "a?c", "acc", "a[bc]*eefc", "a[d"};
const char *s[] = { "abc", "ABC", "abc", "abc", "acd", "acbbccbeefcjkjl", "adcx"};

regex_t cp[sizeof(p)/sizeof(char *)];

char *get_regerror (int errcode, regex_t *compiled)
{
  size_t length = regerror (errcode, compiled, NULL, 0);
  char *buffer = malloc (length);
  (void) regerror (errcode, compiled, buffer, length);
  return buffer;
}


int main()
{
  int n = sizeof(p)/sizeof(char *);
  int i, error;

  for(i=0; i<n; i++)
    {
      error=regcomp(& cp[i], p[i], 0);
      if(!error)
	{
	  printf("pattern: %s , string %s\n", p[i],s[i]);
	  printf("%s\n",  regexec(&cp[i],s[i],0, NULL , 0)?
		 "not match":"match");
	  regfree (&cp[i]);
	}
      else
	{
	  printf("pattern: %s have error: %s\n", 
		 p[i], get_regerror(error, &cp[i]));
	}
    }
  regcomp(&cp[1], p[1], REG_ICASE);
  printf("pattern: %s , string %s (with FLAG_ICASE)\n", p[1],s[1]);
  printf("%s\n",  regexec(&cp[1],s[1],0, NULL , 0)?
		 "not match":"match");
  regfree (&cp[1]);

  char hp[] = "http://(([^./]+)(\\.([^./]+))*)/";
  char sp[] = "http://wiki.woodpecker.org/moin/Hoxide";
  regex_t chp;
  const nresm=10;
  regmatch_t resm[nresm];
  printf("pattern: %s \n" , hp);
  error=regcomp(&chp, hp, REG_EXTENDED);
  if(!error)
    {
      printf("string %s\n",sp);
      if(!regexec(&chp,sp, nresm , resm, 0))
	for(i=0; i<nresm;i++)
	  if(resm[i].rm_so>=0 && resm[i].rm_eo>=0)
	    {
	      printf("metch substring:\n\"");
	      fwrite(&sp[resm[i].rm_so], 
		     resm[i].rm_eo-resm[i].rm_so, 1 ,stdout);
	      printf("\"\nso: %d, eo:%d\n", resm[i].rm_so, resm[i].rm_eo);
	    }
    }
  else
    {
      printf("pattern: %s have some error, errorcode : %s\n",
	     hp, get_regerror(error, &chp));
    }
  

  return 0;
}

}}}

结果(那个处理url的正则表达式可花了我不少时间, 注意re库默认使用POSIX Basic RE而平时常用的是POSIX Extended RE, 偶就错在这里):
{{{
G:\my pro\projects\learning\c\libc>gcc -o re1 re1.c

G:\my pro\projects\learning\c\libc>re1
pattern: abc , string abc
match
pattern: abc , string ABC
not match
pattern: a.c , string abc
match
pattern: a?c , string abc
not match
pattern: acc , string acd
not match
pattern: a[bc]*eefc , string acbbccbeefcjkjl
match
pattern: a[d have error: brackets ([ ]) not balanced
pattern: abc , string ABC (with FLAG_ICASE)
match
pattern: http://(([^./]+)(\.([^./]+))*)/
string http://wiki.woodpecker.org/moin/Hoxide
metch substring:
"http://wiki.woodpecker.org/"
so: 0, eo:27
metch substring:
"wiki.woodpecker.org"
so: 7, eo:26
metch substring:
"wiki"
so: 7, eo:11
metch substring:
".org"
so: 22, eo:26
metch substring:
"org"
so: 23, eo:26

}}}


=== 讨论 ===