diff options
Diffstat (limited to 'Lib/_pyio.py')
| -rw-r--r-- | Lib/_pyio.py | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/Lib/_pyio.py b/Lib/_pyio.py index 78c6dfb4cd..d6eee79e01 100644 --- a/Lib/_pyio.py +++ b/Lib/_pyio.py @@ -62,8 +62,7 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None, 'b' binary mode 't' text mode (default) '+' open a disk file for updating (reading and writing) - 'U' universal newline mode (for backwards compatibility; unneeded - for new code) + 'U' universal newline mode (deprecated) ========= =============================================================== The default mode is 'rt' (open for reading text). For binary random @@ -79,6 +78,10 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None, returned as strings, the bytes having been first decoded using a platform-dependent encoding or using the specified encoding if given. + 'U' mode is deprecated and will raise an exception in future versions + of Python. It has no effect in Python 3. Use newline to control + universal newlines mode. + buffering is an optional integer used to set the buffering policy. Pass 0 to switch buffering off (only allowed in binary mode), 1 to select line buffering (only usable in text mode), and an integer > 1 to indicate @@ -174,6 +177,9 @@ def open(file, mode="r", buffering=-1, encoding=None, errors=None, if "U" in modes: if creating or writing or appending: raise ValueError("can't use U and writing mode at once") + import warnings + warnings.warn("'U' mode is deprecated", + DeprecationWarning, 2) reading = True if text and binary: raise ValueError("can't have text and binary mode at once") |