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'POSIX shared memory module'
from _posixshmem_cffi import lib, ffi
import errno
import os
def shm_open(path, flags, mode=0o777):
'Open a shared memory object. Returns a file descriptor (integer).'
path_utf8 = path.encode("utf-8")
if b'\x00' in path_utf8:
raise ValueError('embedded null character')
while 1:
fd = lib.shm_open(path_utf8, flags, mode)
if fd < 0:
e = ffi.errno
if e != errno.EINTR:
raise OSError(e, os.strerror(e))
else:
return fd
def shm_unlink(path):
'''Remove a shared memory object (similar to unlink()).
Remove a shared memory object name, and, once all processes have unmapped
the object, de-allocates and destroys the contents of the associated memory
region.
'''
path_utf8 = path.encode("utf-8")
if b'\x00' in path_utf8:
raise ValueError('embedded null character')
while 1:
rv = lib.shm_unlink(path_utf8)
if rv < 0:
e = ffi.errno
if e != errno.EINTR:
raise OSError(e, os.strerror(e))
else:
return
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