Novice to see: create a lock file under the Linux operating system

I. Overview

Linux provides a variety of features to achieve file locking. The easiest way to do this is to create a lock file in an atomic way. The so-called "atomic operation" is that when the lock file is created, the system will not allow anything else to happen. This gives the program a way to ensure that the file it creates is unique, and that the file cannot be created by other programs at the same time.

Second, Method

The lock file is just a role that acts as an indicator, and programs need to work together to use them. The lock file is only a suggestive lock, and the opposite is a mandatory lock.

To create a file for use as an indicator, we use the open system call with the O_CREATE and O_EXCL flags. This will allow us to do two things simultaneously with one atomic operation: make sure the file doesn't exist and then create it.

Three, implementation

//file: lock.c#i nclude <unistd.h>#i nclude <stdlib.h>#i nclude < ;stdio.h>#i nclude <fcntl.h>#i nclude <errno.h>int main(){int file_desc;int save_errno;file_desc = open("/tmp/LockFile.test", O_RDWR