badbit标志着系统级的故障如无法恢复的读写错误failbit标志可恢复的错误eofbit是在遇到文件结束符时设置的此时同时还设置了failbit流的状态由badfaileofgood操作提示 每个IO类还定义了三个iostate类型的常量值,分别表示特定的位模式: 1. badbit标志着系统级的故障,如无法恢复的读写错误 2. failbit标志可恢复的错误 3...
badbit =1 eofbit =2 failbit =4 goodbit = 0 验证: if(std::cin.badbit == 1 && std::cin.eofbit == 2 && std::cin.failbit == 4 && std::cin.goodbit == 0) std::cout << "right" << std::endl; 验证结果:right 补充: 在c++ primer 里, 有一条语句: auto old_state = cin...
IO对象不支持拷贝和赋值流的状态: 如果badbit,failbit,eofbit任一个被置位,则检测流状态条件会失败 管理输出缓冲 每个输出流都管理一个缓冲区,保存程序读写的数据 缓冲刷新的原因: 程序结束 缓冲区满 endl等操纵符操纵符unitbuf设置流状态立即刷新(默认cerr设置unitbuf)当读写被关联的流,关联到的流的缓冲区会被刷新...
goodbit : badbit)) & exceptions()) == 0, returns. Otherwise, the function throws an object fail of class basic_ios::failure (27.5.3.1.1), constructed with implementation-defined argument values. So since ios::failbit has been passed through to here we get a non-zero result from the ...
Does it make sense to setstd::ios_base::failbitto throw exceptions, for output streams? As in: 1 2 3 4 5 std::ofstream output_file("out.txt"); output_file.exceptions(std::ios_base::badbit | std::ios_base::failbit);// ... ...
In brief: std::ifstream is; is.exceptions( is.exceptions() | std::ios_base::failbit | std::ios_base::badbit ); // handle different exceptions as 'file not found', 'permission denied' try { is.open("my_valid_file.json"); const auto &jsonF...
因此，一旦你正确读取了整个文件，并且文件中没有留下任何数据，eof()的结果仍然是false（因为你还没有...
因此，一旦你正确读取了整个文件，并且文件中没有留下任何数据，eof()的结果仍然是false（因为你还没有...
static const _Iostate badbit = (_Iostate)0x4; static const _Iostate _Hardfail = (_Iostate)0x10; 3:input.rdstate() & std::ios::failbit 通过位运算的与来判断当前的状态是否是failbit。 不过不能说是等价与if( input.rdstate()==std::ios::failbit ), ...
static const _Iostate badbit = (_Iostate)0x4; static const _Iostate _Hardfail = (_Iostate)0x10; 3:input.rdstate() & std::ios::failbit 通过位运算的与来判断当前的状态是否是failbit。 不过不能说是等价与if( input.rdstate()==std::ios::failbit ), ...