如何在mingw编译器中使用inet_pton()？

Question

我正在尝试为C中已经与IPv4兼容的程序添加IPv6兼容性,但是在编译器方面存在一些问题.目前正在使用mingw32-gcc-4.6.2进行编译,这在使用函数inet_pton时给出了链接错误.

我试过让它为vista编译(因为inet_pton是一个vista函数),但似乎mingw缺少整个函数.

有没有办法将它添加到mingw,或者我可能错过的任何其他选项？

Answer 1

查看我过去的代码 - 在MinGW/GCC中测试:

int inet_pton(int af, const char *src, char *dst)
{
    switch (af)
    {
    case AF_INET:
        return inet_pton4(src, dst);
    case AF_INET6:
        return inet_pton6(src, dst);
    default:
        return -1;
    }
}

..

#define NS_INADDRSZ  4
#define NS_IN6ADDRSZ 16
#define NS_INT16SZ   2

..

int inet_pton4(const char *src, char *dst)
{
    uint8_t tmp[NS_INADDRSZ], *tp;

    int saw_digit = 0;
    int octets = 0;
    *(tp = tmp) = 0;

    int ch;
    while ((ch = *src++) != '\0')
    {
        if (ch >= '0' && ch <= '9')
        {
            uint32_t n = *tp * 10 + (ch - '0');

            if (saw_digit && *tp == 0)
                return 0;

            if (n > 255)
                return 0;

            *tp = n;
            if (!saw_digit)
            {
                if (++octets > 4)
                    return 0;
                saw_digit = 1;
            }
        }
        else if (ch == '.' && saw_digit)
        {
            if (octets == 4)
                return 0;
            *++tp = 0;
            saw_digit = 0;
        }
        else
            return 0;
    }
    if (octets < 4)
        return 0;

    memcpy(dst, tmp, NS_INADDRSZ);

    return 1;
}

...

int inet_pton6(const char *src, char *dst)
{
    static const char xdigits[] = "0123456789abcdef";
    uint8_t tmp[NS_IN6ADDRSZ];

    uint8_t *tp = (uint8_t*) memset(tmp, '\0', NS_IN6ADDRSZ);
    uint8_t *endp = tp + NS_IN6ADDRSZ;
    uint8_t *colonp = NULL;

    /* Leading :: requires some special handling. */
    if (*src == ':')
    {
        if (*++src != ':')
            return 0;
    }

    const char *curtok = src;
    int saw_xdigit = 0;
    uint32_t val = 0;
    int ch;
    while ((ch = tolower(*src++)) != '\0')
    {
        const char *pch = strchr(xdigits, ch);
        if (pch != NULL)
        {
            val <<= 4;
            val |= (pch - xdigits);
            if (val > 0xffff)
                return 0;
            saw_xdigit = 1;
            continue;
        }
        if (ch == ':')
        {
            curtok = src;
            if (!saw_xdigit)
            {
                if (colonp)
                    return 0;
                colonp = tp;
                continue;
            }
            else if (*src == '\0')
            {
                return 0;
            }
            if (tp + NS_INT16SZ > endp)
                return 0;
            *tp++ = (uint8_t) (val >> 8) & 0xff;
            *tp++ = (uint8_t) val & 0xff;
            saw_xdigit = 0;
            val = 0;
            continue;
        }
        if (ch == '.' && ((tp + NS_INADDRSZ) <= endp) &&
                inet_pton4(curtok, (char*) tp) > 0)
        {
            tp += NS_INADDRSZ;
            saw_xdigit = 0;
            break; /* '\0' was seen by inet_pton4(). */
        }
        return 0;
    }
    if (saw_xdigit)
    {
        if (tp + NS_INT16SZ > endp)
            return 0;
        *tp++ = (uint8_t) (val >> 8) & 0xff;
        *tp++ = (uint8_t) val & 0xff;
    }
    if (colonp != NULL)
    {
        /*
         * Since some memmove()'s erroneously fail to handle
         * overlapping regions, we'll do the shift by hand.
         */
        const int n = tp - colonp;

        if (tp == endp)
            return 0;

        for (int i = 1; i <= n; i++)
        {
            endp[-i] = colonp[n - i];
            colonp[n - i] = 0;
        }
        tp = endp;
    }
    if (tp != endp)
        return 0;

    memcpy(dst, tmp, NS_IN6ADDRSZ);

    return 1;
}

作者:Paul Vixie,1996.

Answer 2

我遇到了类似的问题inet_ntop。

您可能需要设置_WIN32_WINNT代表支持的最低 Windows 版本的代码。这将启用仅在较新版本的 Windows 中支持的 API。MSVC 会为您执行此操作，而 MinGW 不会，但它很容易修复。

例如，如果您想支持 Windows 7+，#define _WIN32_WINNT 0x0601

请参阅https://learn.microsoft.com/en-us/cpp/porting/modifying-winver-and-win32-winnt

//
// _WIN32_WINNT version constants
//
#define _WIN32_WINNT_NT4                    0x0400 // Windows NT 4.0
#define _WIN32_WINNT_WIN2K                  0x0500 // Windows 2000
#define _WIN32_WINNT_WINXP                  0x0501 // Windows XP
#define _WIN32_WINNT_WS03                   0x0502 // Windows Server 2003
#define _WIN32_WINNT_WIN6                   0x0600 // Windows Vista
#define _WIN32_WINNT_VISTA                  0x0600 // Windows Vista
#define _WIN32_WINNT_WS08                   0x0600 // Windows Server 2008
#define _WIN32_WINNT_LONGHORN               0x0600 // Windows Vista
#define _WIN32_WINNT_WIN7                   0x0601 // Windows 7
#define _WIN32_WINNT_WIN8                   0x0602 // Windows 8
#define _WIN32_WINNT_WINBLUE                0x0603 // Windows 8.1
#define _WIN32_WINNT_WINTHRESHOLD           0x0A00 // Windows 10
#define _WIN32_WINNT_WIN10                  0x0A00 // Windows 10