int32 len = va_args(va,int32)在x86_64 GNU/Linux上给出了非常大的值

Question

void AppBuf(message_id_type msgID, int32 numPairs, va_list va)

{
int32 len = va_args(va, int32);
....
}

上面的代码在windows(32位和64位)以及linux 32位编译器上运行得非常好.对于以上所有,'len'的值为10.

但是在linux 64位(x86_64 GNU/Linux)上,我得到了一个非常大的值len(50462976),这会使代码的其余部分混乱并在崩溃中结束.

我曾经读过linux 64位编译器中的某些内容已经发生了变化,va_lists但我无法理解这一变化,所以我无法解决我的问题.

有人可以帮我解决这个问题吗？

谢谢.

晴朗

好的,以下是导致这一点的整个代码的详细信息:有人可以帮忙吗？提前致谢.

调用堆栈:

AppendBuffers(int msgID = 0x00000001,int numPairs = 0x00000001,char*va = 0x0007fcb0){注意:这是上面提到的问题所在(长度=非常大)}

LogMsg(int msgID = 0x00000001,int numPairs = 0x00000001,char*arguments = 0x0007fcb0)

LogMsgBuffersV(int msgID = 0x00000001,int numPairs = 0x00000001,char*arguments = 0x0007fcb0)

LogMsgBuffersV(int msgID = 0x00000001,int numPairs = 0x00000001,char*arguments = 0x0007fcb0)

LogMsgBuffers(int msgID = 0x00000001,int numPairs = 0x00000001,...)

实际代码:

void LogMsgBuffers(message_id_type msgID, int32 numPairs, ...)
{

    va_list arguments;
    va_start(arguments, numPairs);

    filter_status_type msgStatus = FilterMsg(msgID);

    if (msgStatus == FILTER_ACCEPT)
    {
        LogMsg(msgID, numPairs, arguments);
    }

    if ((_parentLogger != NULL) && (_oAppenderInheritance))
    {
        //Pass the msg to the parent
        _parentLogger->LogMsgBuffersV(msgID, numPairs, arguments);
    }

    return;
}

void LogMsgBuffersV(message_id_type msgID, int32 numPairs, va_list arguments)
{

    filter_status_type msgStatus = FilterMsg(msgID);

    if (msgStatus == FILTER_ACCEPT)
    {
        //Log msg to the current node
        LogMsg(msgID, numPairs, arguments);
    }

    if ((_parentLogger != NULL) && (_oAppenderInheritance))
    {
        //Pass the msg to the parent
        _parentLogger->LogMsgBuffersV(msgID, numPairs, arguments);

    }
    return;
}

void LogMsgBuffersV(message_id_type msgID, int32 numPairs, va_list arguments)
{
    filter_status_type msgStatus = FilterMsg(msgID);

    if (msgStatus == FILTER_ACCEPT)
    {
        //Log msg to the current node
        LogMsg(msgID, numPairs, arguments);
    }

    if ((_parentLogger != NULL) && (_oAppenderInheritance))
    {
        //Pass the msg to the parent
        _parentLogger->LogMsgBuffersV(msgID, numPairs, arguments);

    }
    return;
}

void LogMsg(message_id_type msgID, int32 numPairs, va_list arguments)
{
    uint32 i;

    for (i = 0; i < _pOwnAppenderVec.size(); i++)
    {
        LoggerAppender *appender = _pOwnAppenderVec[i];
        appender->AppendBuffers(msgID, numPairs, arguments);
    }
    return;
}

void AppendBuffers(message_id_type msgID, int32 numPairs, va_list va)
        {

            for (int32 i = 0; i < numPairs; i++)
            {
                int32 length = va_arg(va, int32);
                uint8* buffer = va_arg(va, uint8*);

                int32 jj;
                for (jj = 10; jj < length; jj += 10)
                {
                    AppendStringA(0, "  %x %x %x %x %x %x %x %x %x %x", buffer[0], buffer[1], buffer[2], buffer[3], buffer[4], buffer[5], buffer[6], buffer[7], buffer[8], buffer[9]);
                    buffer += 10;
                }

                uint8 remainderbuf[10];
                uint32 remainder = length - (jj - 10);
                if (remainder > 0 && remainder <= 10)
                {
                    oscl_memcpy(remainderbuf, buffer, remainder);
                    oscl_memset(remainderbuf + remainder, 0, 10 - remainder);
                    buffer = remainderbuf;
                    AppendStringA(0, "  %x %x %x %x %x %x %x %x %x %x", buffer[0], buffer[1], buffer[2], buffer[3], buffer[4], buffer[5], buffer[6], buffer[7], buffer[8], buffer[9]);
                }
            }
            va_end(va);
        }

Answer 1

AFACIT,va_args不是标准功能.事实上,除了__VA_ARGS__宏之外,谷歌正在将这个问题作为其最佳答案之一.

事实上,没有标准方法来确定va_arg给定的参数数量va_list,并且GCC页面也没有列出任何方法.