ifstream :: rdbuf（）是什么？ [英] What does ifstream::rdbuf() actually do?

问题描述

我有以下代码，它的工作相当不错（除了事实，它是相当缓慢，但我不在乎）。这看起来不直观，这会将infile的整个内容写入outfile。

I have the following code and it works pretty good (other than the fact that it's pretty slow, but I don't care much about that). It doesn't seem intuitive that this would write the entire contents of the infile to the outfile.

// Returns 1 if failed and 0 if successful
int WriteFileContentsToNewFile(string inFilename, string outFilename)
{
    ifstream infile(inFilename.c_str(), ios::binary);
    ofstream outfile(outFilename.c_str(), ios::binary);

    if( infile.is_open() && outfile.is_open() && infile.good() && outfile.good() )
    {
        outfile << infile.rdbuf();

        outfile.close();
        infile.close();
    }
    else
        return 1;

    return 0;
}

任何洞察力？

推荐答案

是的，它在标准中指定，它实际上很简单。 rdbuf（）只是返回指向给定 [io]的基础 basic_streambuf stream object。

Yes, it's specified in the standard and it's actually quite simple. rdbuf() just returns a pointer to the underlying basic_streambuf object for the given [io]stream object.

basic_ostream< ...> 对于指向 basic_streambuf< ...> 的指针的 code> code> $ $ c> basic_streambuf< ...> 。

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