字符编码格式转换

int gb2312toutf8(const char *sourcebuf, size_t sourcelen, char *destbuf, size_t destlen)
{
        iconv_t ict;
        ict = iconv_open("utf-8", "gb2312");
        memset(destbuf, 0, destlen);
        const char **source = &sourcebuf;
        char **dest = &destbuf;
        iconv(ict, (char**)(source), &sourcelen, dest, &destlen);
        iconv_close(ict);
        return 0;
}

libiconv库路径:https://ftp.gnu.org/pub/gnu/libiconv/libiconv-1.15.tar.gz

一般情况下，一个utf-8字符占用3个字符空间，一个gb2312是2个字符空间，转换之前需要申请足够空间存放相应的字符