Optimal lock file method

Question

Windows has an option to open a file with exclusive access rights. Unix doesn\'t.

In order to ensure exclusive access to some file or device, it is common practice

Answer 1

The answer of Hasturkun is the one that has put me on track.

Here is the code I use

#include 
#include 
#include 
#include 

/*! Try to get lock. Return its file descriptor or -1 if failed.
 *
 *  @param lockName Name of file used as lock (i.e. '/var/lock/myLock').
 *  @return File descriptor of lock file, or -1 if failed.
 */
int tryGetLock( char const *lockName )
{
    mode_t m = umask( 0 );
    int fd = open( lockName, O_RDWR|O_CREAT, 0666 );
    umask( m );
    if( fd >= 0 && flock( fd, LOCK_EX | LOCK_NB ) < 0 )
    {
        close( fd );
        fd = -1;
    }
    return fd;
}

/*! Release the lock obtained with tryGetLock( lockName ).
 *
 *  @param fd File descriptor of lock returned by tryGetLock( lockName ).
 *  @param lockName Name of file used as lock (i.e. '/var/lock/myLock').
 */
void releaseLock( int fd, char const *lockName )
{
    if( fd < 0 )
        return;
    remove( lockName );
    close( fd );
}