#include <stdio.h>#include <regex.h>intgnu_regex (regex_pattern, line1, line2)     char *regex_pattern;     char *line1;     char *line2;{  struct re_pattern_buffer pattern_buffer;  struct re_registers regs;  int n, len1, len2;  const char *id;  len1 = strlen (line1);  len2 = strlen (line2);  /* 設定 正則表達式 的語法定義 */  re_syntax_options =    RE_SYNTAX_EGREP | RE_INTERVALS | RE_BACKSLASH_ESCAPE_IN_LISTS;  /* 將 正則表達式 的 pattern buffer 初始化 */  pattern_buffer.allocated = 0;  pattern_buffer.buffer = 0;  pattern_buffer.fastmap = 0;  pattern_buffer.translate = 0;  /* 編譯 正則表達式 */  id = re_compile_pattern (regex_pattern, strlen (regex_pattern),			   &pattern_buffer);  /* 偵測是否有錯誤的發生 */  if (id != NULL)    {      printf (" error on compiling regex1. code = %s\n", id);      exit (1);    }  /* 在字符串 line1 中進行比較，并列出其返回值 */  n = re_match (&pattern_buffer, line1, len1, 0, &regs);  printf (" re_match return = %d\n", n);  /* 在字符串 line1 與字符串 line2 中進行比較，并列出其返回值 */  n =    re_match_2 (&pattern_buffer, line1, len1, line2, len2, 0, &regs,		len1 + len2);  printf (" re_match_2 return = %d\n", n);  /* 在字符串 line1 中進行尋找，并列出其返回值 */  n = re_search (&pattern_buffer, line1, len1, 0, len1, &regs);  printf (" re_search return = %d\n", n);  if (n >= 0)    printf (" re_search string = %s\n", line1);  /* 在字符串 line1 與字符串 line2 中進行尋找，并列出其返回值 */  n =    re_search_2 (&pattern_buffer, line1, len1, line2, len2, 0, len1 + len2,		 &regs, len1 + len2);  if (n >= 0)    {      printf (" re_search_2 return = %d\n", n);      if (n < len1)	printf (" re_search_2 string = %s\n", line1);      else	printf (" re_search_2 string = %s\n", line2);      return 1;    }  printf (" re_search_2 return = %d\n", n);  return n;}main (argc, argv)     int argc;     char **argv;{  FILE *fp;  char line[2][1024];  int i, n, k, j;  /* 檢查參數的個數 */  if (argc != 3)    {      printf ("Usage: %s pattern file\n", argv[0]);      exit (1);    }  /* 打開測試的文件 */  fp = fopen (argv[2], "r");  if (fp == NULL)    {      fprintf (stderr, "Can't open %s.\n", argv[2]);      exit (1);    }  /* 讀取測試文件中的字符串并進行 GNU 接口 Regex 程序的測試 */  j = 1;  fgets (line[0], 1024, fp);  i = strlen (line[0]) - 1;  if (line[0][i] == '\n')    {      line[0][i] = '\0';    }  while (1)    {      n = j & 1;      k = n ^ 1;      if (fgets (line[n], 1024, fp) == NULL)	{	  break;	}      j++;      i = strlen (line[n]) - 1;      if (line[n][i] == '\n')	{	  line[n][i] = '\0';	}      gnu_regex (argv[1], line[k], line[n]);    }  line[n][0] = '\0';  gnu_regex (argv[1], line[k], line[n]);  /* 關閉測試的文件 */  fclose (fp);}