iconv gbk字符转utf8字符

bool gbk2utf8(const char* src, char* dest, size_t inlen)
{
    const char *inbuf = src;
    size_t outlen = inlen * 4;
    char *outbuf = dest;
    memset(outbuf, 0, outlen);
    iconv_t cd = iconv_open("UTF-8", "GBK");
    /* iconv接口会改变inbuf和outbuf，所以不能直接使用src和dest */
    size_t res = iconv(cd, &inbuf, &inlen, &outbuf, &outlen);
    iconv_close(cd);
    return (0 == res) ? true : false;
}

    boost::shared_array<char> ptr_iType(new char[ilen * 4]);
    gbk2utf8(XML_ITYPE_DESC, ptr_iType.get(), ilen);