fl.c File Reference

Basic file lock implementation. More...

#include "fl.h"
#include <assert.h>
#include <fcntl.h>
#include <stddef.h>
#include <sys/file.h>
#include <unistd.h>

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Functions
static int	flopen (struct flock_s *fl)
	Opens the file at the given path and updates the file lock structure with the file descriptor. If the file is already open, the file descriptor is not updated and the function will return successfully. If the file cannot be opened, the error code is returned via the file lock structure.
int	fllock (struct flock_s *fl)
	Locks the file at the given path. If a file descriptor cannot be obtained, or the file cannot be locked, an error code is returned.
int	flunlock (struct flock_s *fl)
	Unlocks the file at the given path. If the file is not open, or the file cannot be unlocked, an error code is returned.

Detailed Description

Basic file lock implementation.

Function Documentation

fllock()

int fllock

(

struct flock_s *

fl

)

Locks the file at the given path. If a file descriptor cannot be obtained, or the file cannot be locked, an error code is returned.

Note

The lock must be initialized with flinit() before calling fllock.

Parameters

fl	The file lock structure.

Returns

0 if successful, otherwise a non-zero error code.

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flopen()

static int flopen ( struct flock_s * fl )

static

Opens the file at the given path and updates the file lock structure with the file descriptor. If the file is already open, the file descriptor is not updated and the function will return successfully. If the file cannot be opened, the error code is returned via the file lock structure.

Parameters

fl	The file lock structure to update.

Returns

0 if successful, otherwise a non-zero error code.

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flunlock()

int flunlock

(

struct flock_s *

fl

)

Unlocks the file at the given path. If the file is not open, or the file cannot be unlocked, an error code is returned.

Parameters

fl	The file lock structure.

Returns

0 if successful, otherwise a non-zero error code.

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