C语言通过关键字从文本中提取有效信息

/* 通过关键字，从文件中提取有用的信息 */

int FindInfoFromFile(char *keyword, char *FilePath, char *OutString)
{
    char *pattern;
    int x, z, lno = 0, cflags = 0;
    char ebuf[128], lbuf[256];
    FILE *fp = NULL;
    regex_t reg;
    regmatch_t pm[10];
    const size_t nmatch = 10;

    pattern = keyword;

    fp = fopen(FilePath, "r" );
    if(fp == NULL)
    {
        fprintf(stderr,"%s[%d]:Cannot open %s\n", __FILE__, __LINE__, FilePath);
        return -1;
    };

    z = regcomp(®, pattern, cflags);
    if (z != 0)
    {
        regerror(z, ®, ebuf, sizeof(ebuf));
        fprintf(stderr, "%s: pattern '%s' \n", ebuf, pattern);
        fclose(fp);
        fp = NULL;
        return -1;
    }

    /* 逐行处理输入的数据 */
    while (fgets (lbuf, sizeof (lbuf), fp))
    {
        ++lno;
        if ((z = (int)strlen(lbuf)) > 0 && lbuf[z - 1] == '\n')
        lbuf[z - 1] = 0;
        /*对每一行应用正则表达式进行匹配 */
        z = regexec (®, lbuf, nmatch, pm, 0);
        if (z == REG_NOMATCH)//没有匹配成功，continue
        {
            continue;
        }
        else if (z != 0)
        {
            regerror (z,®, ebuf, sizeof (ebuf));
            fprintf (stderr, "%s: regcom('%s')\n", ebuf, lbuf);
            fclose(fp);
            fp = NULL;
            return -2;
        }
        /* 输出处理结果 */
        for (x = 0; x < nmatch && pm[x].rm_so != -1; ++x)
        {
            if (!x)
            strcat(OutString, lbuf);
            strcat(OutString, "\n");
        }
    }

    /* 释放正则表达式 */
    fclose(fp);
    fp = NULL;
    regfree (®);
    return 0;
}