【winapi】FormatMessage函数的使用

概述：FormatMessage 函数的使用

const char* SPErrMsg(int errcode)
{
    static char _g_inner_msg[1024];
    memset(_g_inner_msg, 0, sizeof(_g_inner_msg));

#if SP_PLATFORM==SP_PLATFORM_WINDOWS
    if (0==errcode)
    {
        errcode = GetLastError();
    }
    LPTSTR buf = NULL;
    if (::FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
        NULL, errcode, MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US) /* MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT) */,
        (LPTSTR)&buf, 0, NULL))
    {
        // DWORD language_id
        // MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT)
        // MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US)
        // MAKELANGID(LANG_CHINESE_SIMPLIFIED, SUBLANG_CHINESE_SIMPLIFIED)
        // MAKELANGID(LANG_CHINESE_TRADITIONAL, SUBLANG_CHINESE_TRADITIONAL)

        int len = snprintf(_g_inner_msg, sizeof(_g_inner_msg), " [%d]%s", errcode, buf);
        if ( len>2 && _g_inner_msg[len-1]=='\n' && _g_inner_msg[len-2]=='\r' )
        {
            _g_inner_msg[len - 1] = '\0';
            _g_inner_msg[len - 2] = '\0';
        }
        ::LocalFree(buf);
    }
    else
    {
        snprintf(_g_inner_msg, sizeof(_g_inner_msg), " [%d]Unknown error %d", errcode, errcode);
    }
#else
    // https://stackoverflow.com/questions/3219393/stdlib-and-colored-output-in-c
    if (0==errcode)
    {
        errcode = errno;
        errno   = errcode;
    }
    snprintf(_g_inner_msg, sizeof(_g_inner_msg), " [%d]%s", (int)errcode, strerror(errcode));
#endif
    return (_g_inner_msg);
}