跨平台正则表达式POSIX regex的使用

Unix系列平台下有现成的regex库，直接添加即可使用。

windows下可以使用Regex for Windows

相关的函数在regex.h中：

int regcomp (regex_t *compiled,const char *pattern,int cflags)
int regexec (regex_t *compiled,char *string,size_t nmatch,regmatch_t matchptr [],int
　　　           eflags)
void regfree (regex_t *compiled)
size_t regerror (int errcode,regex_t *compiled,char *buffer,size_t length)

正则表达式需要经过regcomp编译，regexec执行，最后regfree释放资源。

测试代码：

#include <iostream>
#include <sys/types.h>
#include <stdio.h>
#include <cstring>
#include <regex.h>

using namespace std;

#define SUBSLEN 10              
#define EBUFLEN 100         
#define BUFLEN 1000

int main(int argc,char** argv)
{
	size_t       len;
	regex_t       re;            
	regmatch_t    subs [SUBSLEN];
	char          matched [BUFLEN];    
	char          errbuf [EBUFLEN];
	int           err;
	
	char          string[] = "!@#$%^&Hello World!@#$%^&*()";
	char          pattern[] = "hello";
   
	printf("String to match: %s\n",string);
	printf("Match pattern: \"%s\"\n",pattern);

	err = regcomp(&re,pattern,REG_EXTENDED);
	if (err)
	{
		len = regerror(err,&re,errbuf,sizeof(errbuf));
		printf("error: regcomp: %s\n",errbuf);
		return 1;
	}

	err = regexec(&re,string,(size_t) SUBSLEN,subs,0);
	if (err == REG_NOMATCH)
	{
		 printf("No match found.\n");
		 regfree(&re);
		 return 0;
	}
	else if (err)
	{  
		 len = regerror(err,sizeof(errbuf));
		 printf("Error in regexec: %s\n",errbuf);
		 return 1;
	}

	printf("Match found.\n");
	for (int i = 0; i <= re.re_nsub; i++)
	{
		len = subs[i].rm_eo - subs[i].rm_so;
		if (i == 0)
		{
			printf ("Substring begin:%d,len = %d   ",(int)subs[i].rm_so,(int)len);
		}
		else
		{
			printf("subexpression_r_r %d begin: %d,i,(int)len);
		}
	   
		memcpy (matched,string + subs[i].rm_so,len);
		matched[len] = '\0';
		printf("Matched substring: %s\n",matched);
	 }


	regfree(&re);
	return 0 ;
}

Linux下编译：

g++ -c regextest.cpp

g++ -o regextest regextest.o -ldl

执行：

davinciyxw@ubuntu:~/develop/regex_test$ ./regextest
String to match: !@#$%^&Hello World!@#$%^&*()
Match pattern: "hello"
Match found.
Substring begin:7,len = 5 Matched substring: hello

---------------------------------------------------------------------------------------------------------

AIX下编译：

xlC -q64 -brtl -o regextest -lpthread regextest.cpp

执行：

[aix][davinciyxw][/Dev/Test]>regextest
String to match: !@#$%^&Hello World!@#$%^&*()
Match pattern: "hello"
Match found.
Substring begin:7,len = 5 Matched substring: hello

---------------------------------------------------------------------------------------------------------

Windows下建立C++控制台程序

添加上文中下载的regex.lib到链接器输入，将regex2.dll拷贝至运行目录编译即可。

执行：

略。