Python in a Nutshell

Name

open

Synopsis

open(file,flags,mode=0777)

Returns a file descriptor, opening or creating a file named file. If open creates the file, it uses mode as the file’s permission bits. flags is an int, normally obtained by bitwise ORing one or more of the following attributes of os:

O_RDONLY , O_WRONLY, O_RDWR

Opens file for read-only, write-only, or read-write respectively (mutually exclusive: exactly one of these attributes must be in flags)

O_NDELAY , O_NONBLOCK

Opens file in non-blocking (no-delay) mode, if the platform supports this

O_APPEND

Appends any new data to file’s previous contents

O_DSYNC , O_RSYNC, O_SYNC, O_NOCTTY

Sets synchronization mode accordingly, if the platform supports this

O_CREAT

Creates file, if file does not already exist

O_EXCL

Raises an exception if file already exists

O_TRUNC

Throws away previous contents of file (incompatible with O_RDONLY)

O_BINARY

Open file in binary rather than text mode on non-Unix platforms (innocuous and without effect on Unix and Unix-like platforms)