fwrite是否缓冲输出？ [英] Does fwrite buffer the output?

问题描述

在C ++中，有一个 std :: fwrite （） ，它将缓冲区写入磁盘上的文件。

In C++, there is an std::fwrite() which writes a buffer to a file on disk.

你能告诉我， fwrite implementation？

Can you please tell me if there is any buffer inside that fwrite implementation?

ie如果我调用fwrite（）多次（说10次），它是否实际调用文件I / O 10不同的时间？

i.e. if I call fwrite() multiple times (say 10 times), does it actually invoke file I/O 10 different times?

我要求这是Ubuntu 10.04环境。

I am asking this for Ubuntu 10.04 environment.

推荐答案

，它被缓冲。缓冲区的大小由 BUFSIZ 定义。 （感谢@ladenedge。）十个足够大的操作将导致十次系统调用。

Yes, it is buffered. The size of the buffer is defined by BUFSIZ. (Thanks @ladenedge.) Ten sufficiently large operations will result in ten system calls.

您还可以使用 std :: setbuf 和 std :: setvbuf 。

You are also allowed to set your own buffer using std::setbuf and std::setvbuf.

cstdio 中的函数从C继承。C ++中的首选接口为 fstream 和 filebuf 。

The functions in cstdio are inherited from C. The preferred interface in C++ is fstream and filebuf.

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