是阅读和不同的字节范围线程安全写入同一个文件？ [英] Is reading and writing to the same file at different bytes-range thread-safe?

问题描述

我有一个文件名为data.txt中总是与50个字节的数据。

I have one file named "data.txt" with always 50 bytes of data.

我有两个线程。

第一个线程，读取字节0到字节50的内容：

The first thread, read content from byte 0 to byte 50:

while(1){
    char buf[50];
    FILE* fp = fopen("data.txt","r");
    fread(buf,1,50,fp);
    /* process data */
    fclose(fp);
}

第二个线程，将数据追加到文件（=总是第一个50字节后）：

The second thread, append data to the file (= always after the first 50 bytes):

while(1){
    FILE* fp = fopen("data.txt","a");
    fwrite("hello\n",1,6,fp);
    fclose(fp);
}

这是解决方案的线程安全和便携？ （不分段错误，数据不一致，...）

Is this solution thread-safe and portable ? (no segmentation fault, no data inconsistency, ...)

推荐答案

我在你的其他相关岗位写的，我所知应该不会崩溃。无论是写入和读取，读取正确我不知道。

As I wrote in your other, related post, to my best knowledge it shouldn't crash. Whether it writes and reads and reads properly I don't know.

如果你是一个POSIX系统上：你有没有使用FIFO（见的 http://man7.org/linux/man-pages/man7/fifo.7.html ）？我有IM pression文件系统是只为你的基础通信需求的一个帮手，即实际的文件并不重要。

If you are on a POSIX system: Have you considered using a fifo (cf. http://man7.org/linux/man-pages/man7/fifo.7.html)? I have the impression that the file system is just a helper for your underlying communication demand, i.e. the actual file is not important.

这篇关于是阅读和不同的字节范围线程安全写入同一个文件？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！