C++二进制文件读写问题在遍历二进制文件的时候，总是在正确执行一定的二进制读取之后，v.fail()就会变成ture
C++二进制文件读写问题
在遍历二进制文件的时候，总是在正确执行一定的二进制读取之后，v.fail()就会变成ture
C/C++ codevoid readType(std::ifstream &v, T *foo) { if(!v.good()) std::cout<< "Attention! Ifstream is not good"<< std::endl; else std::cout<< "Attention! Ifstream is good"<< std::endl; //v.read((char *)foo, sizeof(T)); v.readsome((char *)foo, sizeof(T)); std::cout<<v.gcount()<<" bit has been read"<<endl; if(v.eof()) std::cout<< "ERROR: EOF" <<std::endl; if(v.bad()) std::cout<<"ERROR: badbit" <<std::endl; if(v.fail()) std::cout<<"ERROR: failbit" <<std::endl;}for (int i = 0; i < NumDOFS; ++i) { char len; readType(v, &len); char * buffer_DOFlabel = new char[len]; v.read(buffer_DOFlabel, len); DOFlabels.push_back(string(buffer_DOFlabel)); delete [] buffer_DOFlabel;}
输出结果为：
Attention! Ifstream is good
1 bit has been read
DOFlabel 23's length: 23
DOFlabel 23's contents: khairi:RightFoot <t-Z>
Attention! Ifstream is good
0 bit has been read
DOFlabel 24's length: 26
DOFlabel 24's contents: 屯屯屯屯屯屯屯屯屯屯屯屯屯铪铪铪铪铪
Attention! Ifstream is not good
0 bit has been read
第23此执行能够正确执行，得到的内容是khairi:RightFoot <t-Z>，第24次执行就出现错误。请问这个是由什么引起的？有什么调试方法吗？
[解决办法]readsome()造成的。
看MSDN解释：Read from buffer only.
Remarks
The unformatted input function extracts up to count elements and stores them in the array beginning at _Str. If good is false, the function calls setstate(failbit). Otherwise, it assigns the value of rdbuf->in_avail to N. If N < 0, the function calls setstate(eofbit). Otherwise, it replaces the value stored in N with the smaller of _Count and N, and then calls read(_Str, N). In any case, the function returns gcount.
如果N == 0时（即buffer为NULL），就会造成了上面的结果
[解决办法]//char * buffer_DOFlabel = new char[len]; 改为
char * buffer_DOFlabel = new char[len+1];
试试。
