Maps length bytes from the file specified by the file descriptor fileno, and returns a mmap object. If length is 0, the utmost size of the map shall be the current size of the file when mmap is known as. SHARED creates a mapping that’s shared with all other processes mapping the same areas of the file. WRITE, to specify that the pages may be read or Memory Wave written. It is an error to specify both flags, prot and access. See the description of entry above for info on how to use this parameter. 0. offset must be a multiple of ALLOCATIONGRANULARITY which is equal to PAGESIZE on Unix programs. If trackfd is False, the file descriptor specified by fileno is not going to be duplicated, and the resulting mmap object won't be related to the map’s underlying file. Which means the size() and resize() methods will fail. This mode is helpful to limit the number of open file descriptors.

To make sure validity of the created memory mapping the file specified by the descriptor fileno is internally automatically synchronized with the bodily backing store on macOS. Changed in version 3.13: The trackfd parameter was added. Added in version 3.2: Context supervisor support. Closes the mmap. Subsequent calls to other methods of the article will lead to a ValueError exception being raised. This is not going to close the open file. True if the file is closed. Non-compulsory arguments begin and finish are interpreted as in slice notation. Returns -1 on failure. Changed in model 3.5: Writable bytes-like object is now accepted. Flushes modifications made to the in-memory copy of a file back to disk. Without use of this name there isn't any guarantee that adjustments are written again before the object is destroyed. If offset and dimension are specified, solely changes to the given vary of bytes shall be flushed to disk