Index: Modules/_io/fileio.c
===================================================================
--- Modules/_io/fileio.c	(révision 86919)
+++ Modules/_io/fileio.c	(copie de travail)
@@ -506,7 +506,7 @@
 fileio_readinto(fileio *self, PyObject *args)
 {
     Py_buffer pbuf;
-    Py_ssize_t n;
+    Py_ssize_t n, len;
 
     if (self->fd < 0)
         return err_closed();
@@ -517,9 +517,16 @@
         return NULL;
 
     if (_PyVerify_fd(self->fd)) {
+        len = pbuf.len;
         Py_BEGIN_ALLOW_THREADS
         errno = 0;
-        n = read(self->fd, pbuf.buf, pbuf.len);
+#if defined(MS_WIN64) || defined(MS_WINDOWS)
+        if (len > INT_MAX)
+            len = INT_MAX;
+        n = read(self->fd, pbuf.buf, (int)len);
+#else
+        n = read(self->fd, pbuf.buf, (size_t)len);
+#endif
         Py_END_ALLOW_THREADS
     } else
         n = -1;
@@ -685,7 +692,7 @@
 fileio_write(fileio *self, PyObject *args)
 {
     Py_buffer pbuf;
-    Py_ssize_t n;
+    Py_ssize_t n, len;
 
     if (self->fd < 0)
         return err_closed();
@@ -698,7 +705,14 @@
     if (_PyVerify_fd(self->fd)) {
         Py_BEGIN_ALLOW_THREADS
         errno = 0;
-        n = write(self->fd, pbuf.buf, pbuf.len);
+        len = pbuf.len;
+#if defined(MS_WIN64) || defined(MS_WINDOWS)
+        if (len > INT_MAX)
+            len = INT_MAX;
+        n = write(self->fd, pbuf.buf, (int)len);
+#else
+        n = write(self->fd, pbuf.buf, (size_t)len);
+#endif
         Py_END_ALLOW_THREADS
     } else
         n = -1;
Index: Modules/posixmodule.c
===================================================================
--- Modules/posixmodule.c	(révision 86919)
+++ Modules/posixmodule.c	(copie de travail)
@@ -121,7 +121,7 @@
 #ifdef _MSC_VER         /* Microsoft compiler */
 #define HAVE_GETCWD     1
 #define HAVE_GETPPID    1
-#define HAVE_GETLOGIN   1 
+#define HAVE_GETLOGIN   1
 #define HAVE_SPAWNV     1
 #define HAVE_EXECV      1
 #define HAVE_PIPE       1
@@ -1261,7 +1261,7 @@
 
    The _w represent Unicode equivalents of the aformentioned ANSI functions. */
 
-static int 
+static int
 win32_lstat(const char* path, struct win32_stat *result)
 {
     return win32_xstat(path, result, FALSE, 0);
@@ -1279,7 +1279,7 @@
     return win32_xstat(path, result, TRUE, 0);
 }
 
-static int 
+static int
 win32_stat_w(const wchar_t* path, struct win32_stat *result)
 {
     return win32_xstat_w(path, result, TRUE, 0);
@@ -2317,7 +2317,7 @@
     if (PyArg_ParseTuple(args, "|U:listdir", &po)) {
         WIN32_FIND_DATAW wFileData;
         Py_UNICODE *wnamebuf, *po_wchars;
-        
+
         if (po == NULL) { /* Default arg: "." */
             po_wchars = L".";
             len = 1;
@@ -2719,7 +2719,7 @@
     int result_length;
     PyObject *result;
     wchar_t *path;
-    
+
     if (!PyArg_ParseTuple(args, "u|:_getfinalpathname", &path)) {
         return NULL;
     }
@@ -2740,7 +2740,7 @@
         /* FILE_FLAG_BACKUP_SEMANTICS is required to open a directory */
         FILE_FLAG_BACKUP_SEMANTICS,
         NULL);
-    
+
     if(hFile == INVALID_HANDLE_VALUE) {
         return win32_error_unicode("GetFinalPathNamyByHandle", path);
         return PyErr_Format(PyExc_RuntimeError,
@@ -3052,7 +3052,7 @@
 
     if (GetFileAttributesExW(lpFileName, GetFileExInfoStandard, &info)) {
         is_directory = info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY;
-        
+
         /* Get WIN32_FIND_DATA structure for the path to determine if
            it is a symlink */
         if(is_directory &&
@@ -4231,7 +4231,7 @@
 #endif
     gid_t grouplist[MAX_GROUPS];
 
-    /* On MacOSX getgroups(2) can return more than MAX_GROUPS results 
+    /* On MacOSX getgroups(2) can return more than MAX_GROUPS results
      * This is a helper variable to store the intermediate result when
      * that happens.
      *
@@ -4447,15 +4447,15 @@
 posix_getlogin(PyObject *self, PyObject *noargs)
 {
     PyObject *result = NULL;
-#ifdef MS_WINDOWS    
+#ifdef MS_WINDOWS
     wchar_t user_name[UNLEN + 1];
     DWORD num_chars = sizeof(user_name)/sizeof(user_name[0]);
 
     if (GetUserNameW(user_name, &num_chars)) {
         /* num_chars is the number of unicode chars plus null terminator */
         result = PyUnicode_FromWideChar(user_name, num_chars - 1);
-    } 
-    else 
+    }
+    else
         result = PyErr_SetFromWindowsErr(GetLastError());
 #else
     char *name;
@@ -5139,12 +5139,12 @@
         FILE_FLAG_OPEN_REPARSE_POINT|FILE_FLAG_BACKUP_SEMANTICS,
         0);
     Py_END_ALLOW_THREADS
-    
+
     if (reparse_point_handle==INVALID_HANDLE_VALUE)
     {
         return win32_error_unicode("readlink", path);
     }
-    
+
     Py_BEGIN_ALLOW_THREADS
     /* New call DeviceIoControl to read the reparse point */
     io_result = DeviceIoControl(
@@ -5215,7 +5215,7 @@
     int target_is_directory = 0;
     DWORD res;
     WIN32_FILE_ATTRIBUTE_DATA src_info;
-    
+
     if (!check_CreateSymbolicLinkW())
     {
         /* raise NotImplementedError */
@@ -5230,7 +5230,7 @@
         Py_DECREF(src);
         return NULL;
     }
-    
+
     /* if src is a directory, ensure target_is_directory==1 */
     if(
         GetFileAttributesExW(
@@ -5253,7 +5253,7 @@
     {
         return win32_error_unicode("symlink", PyUnicode_AsUnicode(src));
     }
-    
+
     Py_INCREF(Py_None);
     return Py_None;
 }
@@ -5664,7 +5664,7 @@
 {
     Py_buffer pbuf;
     int fd;
-    Py_ssize_t size;
+    Py_ssize_t size, len;
 
     if (!PyArg_ParseTuple(args, "iy*:write", &fd, &pbuf))
         return NULL;
@@ -5672,8 +5672,15 @@
         PyBuffer_Release(&pbuf);
         return posix_error();
     }
+    len = pbuf.len;
     Py_BEGIN_ALLOW_THREADS
-    size = write(fd, pbuf.buf, (size_t)pbuf.len);
+#if defined(MS_WIN64) || defined(MS_WINDOWS)
+    if (len > INT_MAX)
+        len = INT_MAX;
+    size = write(fd, pbuf.buf, (int)len);
+#else
+    size = write(fd, pbuf.buf, (size_t)len);
+#endif
     Py_END_ALLOW_THREADS
     PyBuffer_Release(&pbuf);
     if (size < 0)