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我在 Windows 7 x32 下使用 RAS API。以下函数返回错误 632 (ERROR_INVALID_SIZE)：

int32_t set_username_passwd(wchar_t *entry_title)
{
    RASDIALPARAMS ras_param;
    ZeroMemory(&ras_param, sizeof(RASDIALPARAMS));
    ras_param.dwSize = sizeof(RASDIALPARAMS);
    memcpy(ras_param.szEntryName, entry_title, wcslen(entry_title));
    memcpy(ras_param.szUserName, L"username", wcslen(L"username"));
    memcpy(ras_param.szPassword, L"password", wcslen(L"password"));
    return RasSetEntryDialParams(0, &ras_param, 0);
}

sizeof(RASDIALPARAMS)返回错误的尺寸？怎么会这样？

或者我错过了什么？

4

1 回答 1

4

RASDIALPARAMS多年来添加了新字段：

#define RASDIALPARAMSW struct tagRASDIALPARAMSW
RASDIALPARAMSW
{
    DWORD dwSize;
    WCHAR szEntryName[ RAS_MaxEntryName + 1 ];
    WCHAR szPhoneNumber[ RAS_MaxPhoneNumber + 1 ];
    WCHAR szCallbackNumber[ RAS_MaxCallbackNumber + 1 ];
    WCHAR szUserName[ UNLEN + 1 ];
    WCHAR szPassword[ PWLEN + 1 ];
    WCHAR szDomain[ DNLEN + 1 ];
#if (WINVER >= 0x401) // 95/NT4 and later
    DWORD dwSubEntry;
    ULONG_PTR dwCallbackId;
#endif
#if (WINVER >= 0x601) // Windows 7 and later
    DWORD dwIfIndex;
#endif
};

因此RASDIALPARAMS，RasSetEntryDialParams()预期的大小取决于特定的 Windows 版本。但是您的应用程序内部的实际大小RASDIALPARAMS取决于WINVER编译期间的定义，如上所示。

因此，当面向 Windows 7 时，WINVER必须将其设置为至少0x601（Windows 7 为 v6.1）的值。如果您使用较低的WINVER值进行编译，则RASDIALPARAMSWindows 7 无法接受的大小将太小。

如果您设置WINVER的值高于您的目标 Windows 版本，您可以在运行时检测操作系统版本并设置ras_param.dwSize为适当的大小，因为sizeof(RASDIALPARAMS)它将比RasSetEntryDialParams()预期的要大。例如：

int32_t set_username_passwd(wchar_t *entry_title)
{
    RASDIALPARAMSW ras_param;
    ZeroMemory(&ras_param, sizeof(ras_param));

    OSVERSIONINFO osvi;
    ZeroMemory(&osvi, sizeof(osvi));

    GetVersionEx(&osvi);

    #if (WINVER >= 0x401)
    if ((osvi.dwMajorVersion < 4) ||
       ((osvi.dwMajorVersion == 4) && (osvi.dwMinVersion < 1)) )
    {
        ras_param.dwSize = offsetof(RASDIALPARAMSW, dwSubEntry);
    }
    else
    #endif
    #if (WINVER >= 0x601)
    if ((osvi.dwMajorVersion < 6) ||
       ((osvi.dwMajorVersion == 6) && (osvi.dwMinVersion < 1)) )
    {
        ras_param.dwSize = offsetof(RASDIALPARAMSW, dwIfIndex);
    }
    else
    #endif
    {
        ras_param.dwSize = sizeof(ras_param);
    }

    wcsncpy(ras_param.szEntryName, entry_title, RAS_MaxEntryName);
    wcsncpy(ras_param.szUserName, L"username", UNLEN);
    wcsncpy(ras_param.szPassword, L"password", PWLEN);

    return RasSetEntryDialParamsW(0, &ras_param, 0);
}

或者，您可以跳过操作系统检查并直接处理ERROR_INVALID_SIZE错误：

int32_t set_username_passwd(wchar_t *entry_title)
{
    RASDIALPARAMSW ras_param;
    ZeroMemory(&ras_param, sizeof(ras_param));

    ras_param.dwSize = sizeof(ras_param);
    wcsncpy(ras_param.szEntryName, entry_title, RAS_MaxEntryName);
    wcsncpy(ras_param.szUserName, L"username", UNLEN);
    wcsncpy(ras_param.szPassword, L"password", PWLEN);

    DWORD dwRet = RasSetEntryDialParamsW(0, &ras_param, 0);
    #if (WINVER >= 0x601)
    if (dwRet == ERROR_INVALID_SIZE)
    {
        ras_param.dwSize = offsetof(RASDIALPARAMSW, dwIfIndex);
        dwRet = RasSetEntryDialParamsW(0, &ras_param, 0);
    }
    #elif (WINVER >= 0x401)
    if (dwRet == ERROR_INVALID_SIZE)
    {
        ras_param.dwSize = offsetof(RASDIALPARAMSW, dwSubEntry);
        dwRet = RasSetEntryDialParamsW(0, &ras_param, 0);
    }
    #endif

    return dwRet;
}
于 2014-04-03T23:47:35.650 回答