msvcrt.locking()

msvcrt.locking(fd, mode, nbytes)

Lock part of a file based on file descriptor fd from the C runtime. Raises OSError on failure. The locked region of the file extends from the current file position for nbytes bytes, and may continue beyond the end of the file. mode must be one of the LK_* constants listed below. Multiple regions in a file may be locked at the same time, but may not overlap. Adjacent regions are not merged; they must be unlocked individually.