Merged revisions 76896,76898 via svnmerge from
svn+ssh://pythondev@svn.python.org/python/trunk
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r76896 | antoine.pitrou | 2009-12-19 22:01:10 +0100 (sam., 19 déc. 2009) | 3 lines
Issue #7545: improve documentation of the `buffering` argument in io.open().
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r76898 | antoine.pitrou | 2009-12-19 22:06:36 +0100 (sam., 19 déc. 2009) | 3 lines
Remove superfetatory paragraph (left there by mistake).
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diff --git a/Lib/_pyio.py b/Lib/_pyio.py
index 04aed8d..a4beb2b 100644
--- a/Lib/_pyio.py
+++ b/Lib/_pyio.py
@@ -82,10 +82,20 @@
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