如何投射向量< unsigned char>到char * [英] How to cast vector<unsigned char> to char*

问题描述

我有这样的缓冲区：

  vector< unsigned char> buf 
  

如何将其转换为char *？

如果我这样做：

 （char *）buf 
  pre> 
 
 
我得到这个错误：
  / home / richard /桌面/ richard / client / src / main.cc：102：错误：无效从类型'std :: vector< unsigned char，std :: allocator< unsigned char& >'to type'char *'
  
对于那些想知道为什么我试图这样做。我需要传递缓冲区到这个函数：
  n_sent = sendto（sk，（char *）buf， ，0，（struct sockaddr *）& server，sizeof（server））; 
  
只接受char *。
解决方案
 
  reinterpret_cast< char *> （& buf [0]）; 
  
向量保证其元素占用连续内存。所以你寻求的数据实际上是第一个元素的地址（注意向量< bool> ，这个技巧将失败）。此外，为什么你的缓冲区向量< char> 不需要reinterpret_cast？
 
 
 
 C ++ 11的更新
 
 
 
  reinterpret_cast< char *>（buf.data（））; 
  
 
I have a buffer like this:
vector<unsigned char> buf
How can I cast it to char*?

If I do:
(char *)buf
I get this error:
/home/richard/Desktop/richard/client/src/main.cc:102: error: invalid cast from type ‘std::vector<unsigned char, std::allocator<unsigned char> >’ to type ‘char*’
For those wondering why I am trying to do this. I need to pass the buffer to this function:
n_sent = sendto(sk,(char *)buf,(int)size,0,(struct sockaddr*) &server,sizeof(server));
And it only accepts char*.
解决方案
reinterpret_cast<char*> (&buf[0]);
The vector guarantees that its elements occupy contiguous memory. So the "data" you seek is actually the address of the first element (beware of vector <bool>, this trick will fail with it). Also, why isn't your buffer vector<char> so that you don't need to reinterpret_cast?

Update for C++11

reinterpret_cast<char*>(buf.data());


                        
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