Issue #12175: FileIO.readall() now raises a ValueError instead of an IOError if
the file is closed.
diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index 1ec6f93..109c82d 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -2467,6 +2467,8 @@
             self.assertRaises(ValueError, f.read)
             if hasattr(f, "read1"):
                 self.assertRaises(ValueError, f.read1, 1024)
+            if hasattr(f, "readall"):
+                self.assertRaises(ValueError, f.readall)
             if hasattr(f, "readinto"):
                 self.assertRaises(ValueError, f.readinto, bytearray(1024))
             self.assertRaises(ValueError, f.readline)
diff --git a/Misc/NEWS b/Misc/NEWS
index 7862e21..fd8f160 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -75,6 +75,9 @@
 Library
 -------
 
+- Issue #12175: FileIO.readall() now raises a ValueError instead of an IOError
+  if the file is closed.
+
 - Issue #12100: Don't reset incremental encoders of CJK codecs at each call to
   their encode() method anymore, but continue to call the reset() method if the
   final argument is True.
diff --git a/Modules/_io/fileio.c b/Modules/_io/fileio.c
index 473919b..0fce1a3 100644
--- a/Modules/_io/fileio.c
+++ b/Modules/_io/fileio.c
@@ -536,6 +536,8 @@
     Py_ssize_t total = 0;
     int n;
 
+    if (self->fd < 0)
+        return err_closed();
     if (!_PyVerify_fd(self->fd))
         return PyErr_SetFromErrno(PyExc_IOError);