Index: Lib/_pyio.py
===================================================================
--- Lib/_pyio.py	(révision 85851)
+++ Lib/_pyio.py	(copie de travail)
@@ -596,6 +596,12 @@
     implementation, but wrap one.
     """
 
+    def getblocking(self) -> bool:
+        self._unsupported("getblocking")
+
+    def setblocking(self, blocking):
+        self._unsupported("setblocking")
+
     def read(self, n: int = None) -> bytes:
         """Read and return up to n bytes.
 
@@ -764,7 +770,13 @@
     def isatty(self):
         return self.raw.isatty()
 
+    def getblocking(self):
+        return self.raw.getblocking()
 
+    def setblocking(self, blocking):
+        self.raw.setblocking(blocking)
+
+
 class BytesIO(BufferedIOBase):
 
     """Buffered I/O implementation using an in-memory bytes buffer."""
@@ -915,6 +927,8 @@
         mode. If n is negative, read until EOF or until read() would
         block.
         """
+        if not self.getblocking():
+            return self.read1(n)
         if n is not None and n < -1:
             raise ValueError("invalid number of bytes to read")
         with self._read_lock:
Index: Modules/_io/fileio.c
===================================================================
--- Modules/_io/fileio.c	(révision 85851)
+++ Modules/_io/fileio.c	(copie de travail)
@@ -57,6 +57,7 @@
     unsigned int closefd : 1;
     PyObject *weakreflist;
     PyObject *dict;
+    int blocking;
 } fileio;
 
 PyTypeObject PyFileIO_Type;
@@ -127,6 +128,7 @@
 
     self = (fileio *) type->tp_alloc(type, 0);
     if (self != NULL) {
+        self->blocking = 1;
         self->fd = -1;
         self->readable = 0;
         self->writable = 0;
@@ -915,7 +917,54 @@
     return PyBool_FromLong(res);
 }
 
+static PyObject *
+fileio_getblocking(fileio *self)
+{
+    return PyBool_FromLong(self->blocking);
+}
 
+#ifdef HAVE_FCNTL_H
+static PyObject *
+fileio_setblocking(fileio *self, PyObject *args)
+{
+    int blocking, ret;
+    long flags;
+
+    if (self->fd < 0)
+        return err_closed();
+
+    if (!PyArg_ParseTuple(args, "i", &blocking))
+        return NULL;
+
+    flags = 0xaabbccdd;
+    Py_BEGIN_ALLOW_THREADS
+    flags = fcntl(self->fd, F_GETFL);
+    Py_END_ALLOW_THREADS
+    if (flags == -1) {
+        PyErr_SetFromErrno(PyExc_IOError);
+        return NULL;
+    }
+
+    if (blocking)
+        flags |= O_NONBLOCK;
+    else
+        flags &= ~O_NONBLOCK;
+
+    Py_BEGIN_ALLOW_THREADS
+    ret = fcntl(self->fd, F_SETFL, flags);
+    Py_END_ALLOW_THREADS
+    if (ret != 0) {
+        PyErr_SetFromErrno(PyExc_IOError);
+        return NULL;
+    }
+
+    self->blocking = blocking;
+
+    Py_RETURN_NONE;
+}
+#endif
+
+
 PyDoc_STRVAR(fileio_doc,
 "file(name: str[, mode: str]) -> file IO object\n"
 "\n"
@@ -992,6 +1041,14 @@
 PyDoc_STRVAR(writable_doc,
 "writable() -> bool.  True if file was opened in a write mode.");
 
+PyDoc_STRVAR(getblocking_doc,
+"getblocking() -> bool. Get blocking or non-blocking mode of the file.");
+
+#ifdef HAVE_FCNTL_H
+PyDoc_STRVAR(setblocking_doc,
+"setblocking(blocking: bool). Set blocking or non-blocking mode of the file.");
+#endif
+
 static PyMethodDef fileio_methods[] = {
     {"read",     (PyCFunction)fileio_read,         METH_VARARGS, read_doc},
     {"readall",  (PyCFunction)fileio_readall,  METH_NOARGS,  readall_doc},
@@ -1008,6 +1065,10 @@
     {"writable", (PyCFunction)fileio_writable, METH_NOARGS,      writable_doc},
     {"fileno",   (PyCFunction)fileio_fileno,   METH_NOARGS,      fileno_doc},
     {"isatty",   (PyCFunction)fileio_isatty,   METH_NOARGS,      isatty_doc},
+    {"getblocking",(PyCFunction)fileio_getblocking,         METH_NOARGS, getblocking_doc},
+#ifdef HAVE_FCNTL_H
+    {"setblocking",(PyCFunction)fileio_setblocking,         METH_VARARGS, setblocking_doc},
+#endif
     {NULL,           NULL}             /* sentinel */
 };