File Objects¶
These APIs are a minimal emulation of the Python 2 C API for built-in file
objects, which used to rely on the buffered I/O (FILE*) support
from the C standard library.  In Python 3, files and streams use the new
io module, which defines several layers over the low-level unbuffered
I/O of the operating system.  The functions described below are
convenience C wrappers over these new APIs, and meant mostly for internal
error reporting in the interpreter; third-party code is advised to access
the io APIs instead.
- 
PyObject* PyFile_FromFd(int fd, const char *name, const char *mode, int buffering, const char *encoding, const char *errors, const char *newline, int closefd)¶
- Return value: New reference.Create a Python file object from the file descriptor of an already opened file fd. The arguments name, encoding, errors and newline can be NULLto use the defaults; buffering can be -1 to use the default. name is ignored and kept for backward compatibility. ReturnNULLon failure. For a more comprehensive description of the arguments, please refer to theio.open()function documentation.Warning Since Python streams have their own buffering layer, mixing them with OS-level file descriptors can produce various issues (such as unexpected ordering of data). Changed in version 3.2: Ignore name attribute. 
- 
int PyObject_AsFileDescriptor(PyObject *p)¶
- Return the file descriptor associated with p as an - int. If the object is an integer, its value is returned. If not, the object’s- fileno()method is called if it exists; the method must return an integer, which is returned as the file descriptor value. Sets an exception and returns- -1on failure.
- 
PyObject* PyFile_GetLine(PyObject *p, int n)¶
- Return value: New reference.Equivalent to p.readline([n]), this function reads one line from the object p. p may be a file object or any object with areadline()method. If n is0, exactly one line is read, regardless of the length of the line. If n is greater than0, no more than n bytes will be read from the file; a partial line can be returned. In both cases, an empty string is returned if the end of the file is reached immediately. If n is less than0, however, one line is read regardless of length, butEOFErroris raised if the end of the file is reached immediately.
- 
int PyFile_SetOpenCodeHook(Py_OpenCodeHookFunction handler)¶
- Overrides the normal behavior of - io.open_code()to pass its parameter through the provided handler.- The handler is a function of type - PyObject *(*)(PyObject *path, void *userData), where path is guaranteed to be- PyUnicodeObject.- The userData pointer is passed into the hook function. Since hook functions may be called from different runtimes, this pointer should not refer directly to Python state. - As this hook is intentionally used during import, avoid importing new modules during its execution unless they are known to be frozen or available in - sys.modules.- Once a hook has been set, it cannot be removed or replaced, and later calls to - PyFile_SetOpenCodeHook()will fail. On failure, the function returns -1 and sets an exception if the interpreter has been initialized.- This function is safe to call before - Py_Initialize().- Raises an auditing event - setopencodehookwith no arguments.- New in version 3.8.