问题描述
在C ++中，有一个，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.
您还可以使用和。
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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