In addition to Weibo, there is also WeChat
Please pay attention
WeChat public account
Shulou
2025-01-20 Update From: SLTechnology News&Howtos shulou NAV: SLTechnology News&Howtos > Servers >
Share
Shulou(Shulou.com)06/01 Report--
This article mainly introduces "how to create a lock file under the Linux operating system". In the daily operation, I believe that many people have doubts about how to create a lock file under the Linux operating system. The editor consulted all kinds of materials and sorted out a simple and easy-to-use operation method. I hope it will be helpful to answer the doubt of "how to create a lock file under the Linux operating system". Next, please follow the editor to study!
I. Overview
Linux provides a variety of features for file locking. The easiest way is to create a lock file in an atomic way. The so-called "atomic operation" is that when you create a lock file, the system will not allow anything else to happen. This provides a way for a program to ensure that the file it creates is sexual, and that the file cannot be created by other programs at the same time.
2. Methods
Lock files simply act as indicators, and programs need to work with each other to use them. Lock files are only recommended locks, as opposed to mandatory locks.
To create a file to use as an indicator, we use the open system call with the O_CREATE and O_EXCL flags. This allows us to do two things at the same time as an atomic operation: make sure the file doesn't exist, and then create it.
III. Realization
/ file: lock.c#i nclude # I nclude # i nclude int main () {int file_desc;int save_errno;file_desc = open ("/ tmp/LockFile.test", O_RDWR | O_CREAT | O_EXCL, 0444); if (file_desc < 0) {save_errno = errno;printf ("Open failed with error is% d\ n", save_errno);} else {printf ("Open succeeded\ n");} exit (EXIT_SUCCESS);}
* run the program for the second time:
$lock
The output is as follows:
Open succeeded
Let's run the program again:
$lock
The output is as follows:
Open failed with error is 17
Analysis:
The program was executed successfully the next time the program was run because the file does not exist. For subsequent execution, failed because the file already exists. If you want the program to execute successfully again, you must delete the lock file.
In Linux systems, the error number 17 usually represents EEXIST, which is used to indicate that a file already exists. The error number is defined in the header file errno.h or (more commonly) the header file it contains.
At this point, the study on "how to create lock files under the Linux operating system" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!
Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.
Views: 0
*The comments in the above article only represent the author's personal views and do not represent the views and positions of this website. If you have more insights, please feel free to contribute and share.
Continue with the installation of the previous hadoop.First, install zookooper1. Decompress zookoope
"Every 5-10 years, there's a rare product, a really special, very unusual product that's the most un
© 2024 shulou.com SLNews company. All rights reserved.