std::fstream 不创建文件 [英] std::fstream doesn't create file

问题描述

我正在尝试将 std::fstream 用于 io to file，如果文件不存在，我想创建该文件.

I am trying to use std::fstream for io to file, and I want to create the file if it doesn't already exist.

  std::fstream my_stream
  my_stream.open("my_file_name",std::fstream::binary | std::fstream::in | std::fstream::out);
  if(!my_stream)
      std::cout<<"error"<<strerror(errorno);

我得到这个结果:没有这样的文件或目录."

I get this result: "No such file or directory."

在这种情况下如何创建文件?

How can I create the file in this case?

推荐答案

您在调用 fstream::open().这是已知强制它需要现有文件.

You're specifying std::fstream::in in your call to fstream::open(). This is known to force it to require an existing file.

从你的 mode 参数中删除 std::fstream::in，或者指定 std::fstream::trunc 除了其他标志.

Either remove std::fstream::in from your mode argument, or specify std::fstream::trunc in addition to the other flags.

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