diff options
Diffstat (limited to 'Lib/io.py')
| -rw-r--r-- | Lib/io.py | 18 |
1 files changed, 14 insertions, 4 deletions
@@ -124,10 +124,20 @@ def open(file, mode="r", buffering=None, 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. - buffering is an optional integer used to set the buffering policy. By - default full buffering is on. Pass 0 to switch buffering off (only - allowed in binary mode), 1 to set line buffering, and an integer > 1 - for full buffering. + 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 + the size of a fixed-size chunk buffer. When no buffering argument is + given, the default buffering policy works as follows: + + * Binary files are buffered in fixed-size chunks; the size of the buffer + is chosen using a heuristic trying to determine the underlying device's + "block size" and falling back on `io.DEFAULT_BUFFER_SIZE`. + On many systems, the buffer will typically be 4096 or 8192 bytes long. + + * "Interactive" text files (files for which isatty() returns True) + use line buffering. Other text files use the policy described above + for binary files. encoding is the name of the encoding used to decode or encode the file. This should only be used in text mode. The default encoding is |