C++ 错误 C2064：术语不计算为采用 0 个参数的函数
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error C2064: term does not evaluate to a function taking 0 arguments
提问by GoldenLee
everyone!
I maintain a group of channel data in a map container, from which an individual channel data can be accessed by its channle name. With regards to this, I write a simple function GetIRChannelData(please see the following code). When compliing, the statement pusIRChannelData = cit->second();throwed an error, which read
每个人！我在地图容器中维护了一组频道数据，从中可以通过其频道名称访问单个频道数据。关于这个，我写了一个简单的函数GetIRChannelData（请看下面的代码）。编译时，该语句抛出pusIRChannelData = cit->second();一个错误，其中读取
error C2064: term does not evaluate to a function taking 0 arguments
All the function to do is nothing but to search for a given channel name/ID in the map container, and assign it data pointer to a temporal pointer if found. Would you please show me what's wrong?
所有要做的功能就是在地图容器中搜索给定的频道名称/ID，如果找到，则将数据指针分配给时间指针。你能告诉我有什么问题吗？
const Array2D<unsigned short>* GetIRChannelData(std::string sChannelName) const
{
const Array2D<unsigned short>* pusIRChannelData = NULL;
for (std::map<std::string, Array2D<unsigned short>* >::const_iterator cit = m_usIRDataPool.begin(); cit != m_usIRDataPool.end(); ++cit)
{
std::string sKey = cit->first;
if (sKey == sChannelName)
{
pusIRChannelData = cit->second(); // Error occurred on this line
break;
}
}
return pusIRChannelData;
}
回答by Dennis Zickefoose
The error message is pretty clear... you call a function that doesn't exist. map::iteratorpoints to a std::pair, which has two member objects, firstand second. Note that these are not functions. Remove the ()from the line in question and the error should go away.
错误消息非常清楚……您调用了一个不存在的函数。 map::iterator指向 a std::pair，它有两个成员对象，first和second。请注意，这些不是函数。()从有问题的行中删除 ，错误应该消失。
回答by geekosaur
It looks like cit->seconddoesn't identify a function pointer. The definition of your iterator claims it's a pointer to (Array2D<unsigned short>); pusIRChannelDatais an (Array2D *), so you probably want cit->secondinstead of cit->second()(which tries to invoke your (Array2D *)as a function).
看起来cit->second没有识别函数指针。您的迭代器的定义声称它是一个指向(Array2D<unsigned short>); pusIRChannelData是一个(Array2D *)，所以你可能想要cit->second而不是cit->second()（它试图将你的(Array2D *)作为函数调用）。
