自定义冲洗实现 [英] Custom flush implementation

问题描述

我想要遵循此问题在 streambuf 。 htmlrel =nofollow> Rcpp 。有人贡献了基本的行为，让我们可以写如下

I'm trying to follow the logic of this question to create a custom streambuf in Rcpp. Someone contributed the basic behaviour that allows us to write things like

Rcout << "some text" ;

其中我们实现了 xsputn 和 overflow 重定向到 Rprintf 函数。

where we implemented xsputn and overflow to redirect to Rprintf function.

std::streamsize Rcpp::Rstreambuf::xsputn(const char *s, std::streamsize num ) {
    Rprintf( "%.*s", num, s );
    return num;
}

int Rcpp::Rstreambuf::overflow(int c ) {
    if (c != EOF) {
        Rprintf( "%.1s", &c );
    }
    return c;
}

我想实现刷新，即支持这种语法：

I would like to implement flushing too, i.e. support this syntax:

Rcout << "some text" << std::flush ;

我需要实现哪种方法，以便 flush manipulator是否在我的自定义流上工作？

Which method do I need to implement so that the flush manipulator works on my custom stream ?

推荐答案

$ c>函数（类似于 filebuf ）：

It is sync() function (like in filebuf):

protected:
virtual int sync()

$ b b

base_streambuf<> :: sync（）的基本版本不做任何操作，必须覆盖它以与底层流进行某些同步。

Base version of base_streambuf<>::sync() does nothing, one must overwrite it to make some synchronization with underlying stream.

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