File Objects¶
These APIs are a minimal emulation of the Python 2 C API for built-in fileobjects, which used to rely on the buffered I/O (FILE*) supportfrom the C standard library. In Python 3, files and streams use the newio module, which defines several layers over the low-level unbufferedI/O of the operating system. The functions described below areconvenience C wrappers over these new APIs, and meant mostly for internalerror reporting in the interpreter; third-party code is advised to accesstheio APIs instead.
PyFile_FromFd(int fd, const char *name, const char *mode, int buffering, const char *encoding, const char *errors, const char *newline, int closefd)¶Create a Python file object from the file descriptor of an alreadyopened filefd. The argumentsname,encoding,errors andnewlinecan beNULL to use the defaults;buffering can be-1 to use thedefault.name is ignored and kept for backward compatibility. ReturnNULL on failure. For a more comprehensive description of the arguments,please refer to the
io.open()function documentation.Warning
Since Python streams have their own buffering layer, mixing them withOS-level file descriptors can produce various issues (such as unexpectedordering of data).
Changed in version 3.2:Ignorename attribute.
- int
PyObject_AsFileDescriptor(PyObject *p)¶ Return the file descriptor associated withp as an
int. If theobject is an integer, its value is returned. If not, theobject’sfileno()method is called if it exists; themethod must return an integer, which is returned as the file descriptorvalue. 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 theobjectp.p may be a file object or any object with areadline()method. Ifn is0, exactly one line is read, regardless of the length ofthe line. Ifn is greater than0, no more thann bytes will be readfrom the file; a partial line can be returned. In both cases, an empty stringis returned if the end of the file is reached immediately. Ifn is less than0, however, one line is read regardless of length, butEOFErrorisraised if the end of the file is reached immediately.