如何附加到fstream fstream :: app标志的文件似乎不起作用

Question

我只想写(追加)到日志文件.我在这里查了一下:http:
//www.cplusplus.com/reference/iostream/fstream/open/

所以这就是我所做的

#include <fstream>

fstream outfile;

//outfile.open("/tmp/debug.txt" );  // works, simply for writing
outfile.open("/tmp/debug.txt", fstream::app );  // does nothing

outfile << "START" << endl;

outfile.close();

Answer 1

fstream::app|fstream::out而不是fstream::app.app没有指定就没有意义out(人们可能会认为它应该暗示out,但事实并非如此).