flopen(3bsd)

💖 flopen(3bsd) 💖

okay bestie, welcome to the flopen page from section 3bsd of the local manual — yes it's literally called flopen(3bsd), that's the whole name, we're not being weird about it ✨

🌸 NAME 🌸

flopen, flopenat — Reliably open and lock a file

no fr, that's the whole vibe: open it AND lock it, no cap 🔒

🎀 LIBRARY 🎀

Utility functions from BSD systems (libbsd, -lbsd)

✨ SYNOPSIS ✨

#include <sys/fcntl.h>
#include <libutil.h>

(See libbsd(7) for include usage.)

int
flopen(const char *path, int flags);

int
flopen(const char *path, int flags, mode_t mode);

int
flopenat(int fd, const char *path, int flags);

int
flopenat(int fd, const char *path, int flags, mode_t mode);

🦋 DESCRIPTION 🦋

so the flopen() function opens or creates a file and acquires an exclusive lock on it 💅 it is essentially equivalent with calling open() with the same parameters followed by flock() with an operation argument of LOCK_EX, except that flopen() will attempt to detect and handle races that may occur between opening / creating the file and locking it 🫶

the way that makes it chef's kiss for opening lock files, PID files, spool files, mailboxes and other kinds of files which are used for synchronization between processes — it's giving main character energy for process coordination fr fr 👑

If flags includes O_NONBLOCK and the file is already locked, flopen() will fail and set errno to EWOULDBLOCK 😭 (no waiting around for you, bestie, it's busy)

As with open(), the additional mode argument is required if flags includes O_CREAT ⚠️

The flopenat() function is equivalent to the flopen() function except in the case where the path specifies a relative path. In this case the file to be opened is determined relative to the directory associated with the file descriptor fd instead of the current working directory 🌈

If flopenat() is passed the special value AT_FDCWD in the fd parameter, the current working directory is used and the behavior is identical to a call to flopen() ✨

💜 RETURN VALUES 💜

If successful, flopen() returns a valid file descriptor 🎉 Otherwise, it returns -1, and sets errno as described in flock(2) and open(2) 💀

🍓 SEE ALSO 🍓

• errno(2)
• flock(2)
• open(2)

👑 AUTHORS 👑

The flopen function and this manual page were written by Dag-Erling Smørgrav <des@FreeBSD.org> 🌟 absolute icon, we love to see it

and that's the page, bestie!! this cutie came to you from Debian, dated July 28, 2017, and it lives in the flopen(3bsd) manual 💖 go lock some files responsibly, mwah 🎀✨