Os x pdf library

Launch Demo. More Frameworks. More Integrations. Contact Sales Try for Free. File Types. See all Capabilities. By Industry. React Native. More Languages. Free Trial Support. For creating temporary files and directories see the tempfile module, and for high-level file and directory handling see the shutil module. The design of all built-in operating system dependent modules of Python is such that as long as the same functionality is available, it uses the same interface; for example, the function os.

Extensions peculiar to a particular operating system are also available through the os module, but using them is of course a threat to portability. All functions accepting path or file names accept both bytes and string objects, and result in an object of the same type, if a path or file name is returned.

All functions in this module raise OSError or subclasses thereof in the case of invalid or inaccessible file names and paths, or other arguments that have the correct type, but are not accepted by the operating system. An alias for the built-in OSError exception. The name of the operating system dependent module imported. The following names have currently been registered: 'posix' , 'nt' , 'java'. In Python, file names, command line arguments, and environment variables are represented using the string type.

On some systems, decoding these strings to and from bytes is necessary before passing them to the operating system. Python uses the filesystem encoding and error handler to perform this conversion see sys. Changed in version 3. The file system encoding must guarantee to successfully decode all bytes below See also the locale encoding. New in version 3. Use UTF-8 as the filesystem encoding. On Unix, os. As a consequence of the changes in those lower level APIs, other higher level APIs also exhibit different default behaviours:.

Command line arguments, environment variables and filenames are decoded to text using the UTF-8 encoding. However, they still use the strict error handler by default so that attempting to open a binary file in text mode is likely to raise an exception rather than producing nonsense data. In such legacy locales, the interpreter will default to enabling UTF-8 mode unless explicitly instructed not to do so.

Its value can be read from sys. See also the UTF-8 mode on Windows and the filesystem encoding and error handler. Availability : Unix. A mapping object where keys and values are strings that represent the process environment.

This mapping is captured the first time the os module is imported, typically during Python startup as part of processing site. Changes to the environment made after this time are not reflected in os.

This mapping may be used to modify the environment as well as query the environment. On Unix, keys and values use sys. Use environb if you would like to use a different encoding. Calling putenv directly does not change os. Refer to the system documentation for putenv. You can delete items in this mapping to unset environment variables. Bytes version of environ : a mapping object where both keys and values are bytes objects representing the process environment.

These functions are described in Files and Directories. Encode path-like filename to the filesystem encoding and error handler ; return bytes unchanged. PathLike interface. Decode the path-like filename from the filesystem encoding and error handler ; return str unchanged.

If str or bytes is passed in, it is returned unchanged. In all other cases, TypeError is raised. An abstract base class for objects representing a file system path, e. The method should only return a str or bytes object, with the preference being for str. On Unix, keys and values are decoded with sys. Use os. Availability : most flavors of Unix, Windows. Availability : most flavors of Unix.

Returns the list of directories that will be searched for a named executable, similar to a shell, when launching a process. By default, when env is None , environ is used. Return the effective group id of the current process. Return list of group ids that user belongs to. If group is not in the list, it is included; typically, group is specified as the group ID field from the password record for user.

On macOS, getgroups behavior differs somewhat from other Unix platforms. If the Python interpreter was built with a deployment target of If built with a deployment target greater than Return the name of the user logged in on the controlling terminal of the process.

For most purposes, it is more useful to use getpass. Availability : Unix, Windows. Return the process group id of the process with process id pid. If pid is 0, the process group id of the current process is returned. When the parent process has exited, on Unix the id returned is the one of the init process 1 , on Windows it is still the same id, which may be already reused by another process.

Get program scheduling priority. A zero value for who denotes respectively the calling process, the process group of the calling process, or the real user ID of the calling process. Parameters for the getpriority and setpriority functions. Call the system initgroups to initialize the group access list with all of the groups of which the specified username is a member, plus the specified group id.

Set the environment variable named key to the string value. Such changes to the environment affect subprocesses started with os. Assignments to items in os. Raises an auditing event os. Set the list of supplemental group ids associated with the current process to groups.

This operation is typically available only to the superuser. On macOS, the length of groups may not exceed the system-defined maximum number of effective group ids, typically See the documentation for getgroups for cases where it may not return the same group list set by calling setgroups.

Call the system call setpgrp or setpgrp 0, 0 depending on which version is implemented if any. See the Unix manual for the semantics. Call the system call setpgid to set the process group id of the process with id pid to the process group with id pgrp. Set program scheduling priority. The default priority is 0; lower priorities cause more favorable scheduling. Call the system call getsid. Call the system call setsid. Return the error message corresponding to the error code in code. True if the native OS type of the environment is bytes eg.

False on Windows. Returns information identifying the current operating system. The return value is an object with five attributes:. For backwards compatibility, this object is also iterable, behaving like a five-tuple containing sysname , nodename , release , version , and machine in that order.

Some systems truncate nodename to 8 characters or to the leading component; a better way to get the hostname is socket. Availability : recent flavors of Unix. Unset delete the environment variable named key. Deletion of items in os. These functions create new file objects. See also open for opening file descriptors. Return an open file object connected to the file descriptor fd. This is an alias of the open built-in function and accepts the same arguments.

The only difference is that the first argument of fdopen must always be an integer. File descriptors are small integers corresponding to a file that has been opened by the current process. For example, standard input is usually file descriptor 0, standard output is 1, and standard error is 2.

Further files opened by a process will then be assigned 3, 4, 5, and so forth. The fileno method can be used to obtain the file descriptor associated with a file object when required. Note that using the file descriptor directly will bypass the file object methods, ignoring aspects such as internal buffering of data.

Equivalent to but much faster than :. The files pointed by src and dst must reside in the same filesystem, otherwise an OSError is raised with errno set to errno. This copy is done without the additional cost of transferring data from the kernel to user space and then back into the kernel. Additionally, some filesystems could implement extra optimizations.

The copy is done as if both files are opened as binary. Return a string describing the encoding of the device associated with fd if it is connected to a terminal; else return None. Return a duplicate of file descriptor fd. The new file descriptor is non-inheritable. On Windows, when duplicating a standard stream 0: stdin, 1: stdout, 2: stderr , the new file descriptor is inheritable.

Duplicate file descriptor fd to fd2 , closing the latter first if necessary. Return fd2. The new file descriptor is inheritable by default or non-inheritable if inheritable is False. Previously, None was always returned.

Change the mode of the file given by fd to the numeric mode. See the docs for chmod for possible values of mode. As of Python 3.

Change the owner and group id of the file given by fd to the numeric uid and gid. To leave one of the ids unchanged, set it to See chown. Return system configuration information relevant to an open file. Some platforms define additional names as well. For configuration variables not included in that mapping, passing an integer for name is also accepted. If name is a string and is not known, ValueError is raised.

Get the status of the file descriptor fd. The stat function. Return information about the filesystem containing the file associated with file descriptor fd , like statvfs. Force write of file with filedescriptor fd to disk. Truncate the file corresponding to file descriptor fd , so that it is at most length bytes in size. Return True if the file descriptor fd is open and connected to a tty -like device, else False.

Flags that specify what action lockf will take. Return the new cursor position in bytes, starting from the beginning. Parameters to the lseek function. Their values are 0, 1, and 2, respectively. Open the file path and set various flags according to flags and possibly its mode according to mode. When computing mode , the current umask value is first masked out.

Return the file descriptor for the newly opened file. Raises an auditing event open with arguments path , mode , flags. For normal usage, use the built-in function open , which returns a file object with read and write methods and many more. To wrap a file descriptor in a file object, use fdopen. The following constants are options for the flags parameter to the open function.

They can be combined using the bitwise OR operator. Some of them are not available on all platforms. Open a new pseudo-terminal pair.

Return a pair of file descriptors master, slave for the pty and the tty, respectively. The new file descriptors are non-inheritable. For a slightly more portable approach, use the pty module. Availability : some flavors of Unix. Create a pipe. Return a pair of file descriptors r, w usable for reading and writing, respectively. Create a pipe with flags set atomically. Ensures that enough disk space is allocated for the file specified by fd starting from offset and continuing for len bytes.

Announces an intention to access data in a specific pattern thus allowing the kernel to make optimizations. The advice applies to the region of the file specified by fd starting at offset and continuing for len bytes. Read at most n bytes from file descriptor fd at a position of offset , leaving the file offset unchanged. Return a bytestring containing the bytes read.

If the end of the file referred to by fd has been reached, an empty bytes object is returned. Read from a file descriptor fd at a position of offset into mutable bytes-like objects buffers , leaving the file offset unchanged. Transfer data into each buffer until it is full and then move on to the next buffer in the sequence to hold the rest of the data. Return the total number of bytes actually read which can be less than the total capacity of all the objects. Combine the functionality of os.

Availability : Linux 2. Using flags requires Linux 4. Do not wait for data which is not immediately available. If this flag is specified, the system call will return instantly if it would have to read data from the backing storage or wait for a lock. If some data was successfully read, it will return the number of bytes read. If no bytes were read, it will return -1 and set errno to errno. Availability : Linux 4. Allows block-based filesystems to use polling of the device, which provides lower latency, but may use additional resources.

Write the bytestring in str to file descriptor fd at position of offset , leaving the file offset unchanged. Write the buffers contents to file descriptor fd at a offset offset , leaving the file offset unchanged. Buffers are processed in array order. Entire contents of the first buffer is written before proceeding to the second, and so on. This flag effect applies only to the data range written by the system call.

This flag is meaningful only for os. The offset argument does not affect the write operation; the data is always appended to the end of the file. However, if the offset argument is -1 , the current file offset is updated.

Return the number of bytes sent. When EOF is reached return 0. The first function notation is supported by all platforms that define sendfile. It returns the same as the first case. Cross-platform applications should not use headers , trailers and flags arguments. For a higher-level wrapper of sendfile , see socket. Set the blocking mode of the specified file descriptor. Parameters to the sendfile function, if the implementation supports them.

At least one of the file descriptors must refer to a pipe. The offset associated to the file descriptor that refers to a pipe must be None.

Upon successful completion, returns the number of bytes spliced to or from the pipe. A return value of 0 means end of input. If src refers to a pipe, then this means that there was no data to transfer, and it would not make sense to block because there are no writers connected to the write end of the pipe.

Read from a file descriptor fd into a number of mutable bytes-like objects buffers. Return the process group associated with the terminal given by fd an open file descriptor as returned by os. Set the process group associated with the terminal given by fd an open file descriptor as returned by os.

Return a string which specifies the terminal device associated with file descriptor fd. If fd is not associated with a terminal device, an exception is raised. Write the contents of buffers to file descriptor fd. If the file descriptor is not connected to a terminal, an OSError is raised. A subclass of tuple, holding columns, lines of the terminal window size. Since Python 3.

On UNIX, non-inheritable file descriptors are closed in child processes at the execution of a new program, other file descriptors are inherited. On Windows, non-inheritable handles and file descriptors are closed in child processes, except for standard streams file descriptors 0, 1 and 2: stdin, stdout and stderr , which are always inherited. Availability : Windows. However, some functions now alternatively accept an open file descriptor for their path argument. The function will then operate on the file referred to by the descriptor.

You can check whether or not path can be specified as a file descriptor for a particular function on your platform using os. If this functionality is unavailable, using it will raise a NotImplementedError. Return True if access is allowed, False if not. See the Unix man page access 2 for more information. This function can support specifying paths relative to directory descriptors and not following symlinks.

If it is unavailable, using it will raise a NotImplementedError. Using access to check if a user is authorized to e. For example:. Values to pass as the mode parameter of access to test the existence, readability, writability and executability of path , respectively.

This function can support specifying a file descriptor. This is where you need to be careful - you need to drop the document over the thumbnail of the previous document last page, not underneath it. The difference is quite easy to spot - when doing it right Preview will show a border around the thumbnail in the sidebar, instead of a line underneath it - see image below.

Then you need to save the file, perhaps with a new name.