Module « fcntl » Python 3.11.3

Fonction lockf - module fcntl

Signature de la fonction lockf

def lockf(fd, cmd, len=0, start=0, whence=0) 

Description

help(fcntl.lockf)

A wrapper around the fcntl() locking calls.

`fd` is the file descriptor of the file to lock or unlock, and operation is one
of the following values:

    LOCK_UN - unlock
    LOCK_SH - acquire a shared lock
    LOCK_EX - acquire an exclusive lock

When operation is LOCK_SH or LOCK_EX, it can also be bitwise ORed with
LOCK_NB to avoid blocking on lock acquisition.  If LOCK_NB is used and the
lock cannot be acquired, an OSError will be raised and the exception will
have an errno attribute set to EACCES or EAGAIN (depending on the operating
system -- for portability, check for either value).

`len` is the number of bytes to lock, with the default meaning to lock to
EOF.  `start` is the byte offset, relative to `whence`, to that the lock
starts.  `whence` is as with fileobj.seek(), specifically:

    0 - relative to the start of the file (SEEK_SET)
    1 - relative to the current buffer position (SEEK_CUR)
    2 - relative to the end of the file (SEEK_END)