# HG changeset patch
# Parent  d4b68ac6c4eaf51dd06a339a16f188737199c78e
Issue #25495: Clarify data length limit for b2a_base64()

diff -r d4b68ac6c4ea Doc/library/binascii.rst
--- a/Doc/library/binascii.rst	Tue Nov 03 22:43:31 2015 -0800
+++ b/Doc/library/binascii.rst	Thu Nov 05 10:57:14 2015 +0000
@@ -9,7 +9,7 @@
 
 .. index::
    module: uu
-   module: base64
+   single: base 64
    module: binhex
 
 The :mod:`binascii` module contains a number of methods to convert between
@@ -45,8 +45,11 @@
 .. function:: b2a_base64(data)
 
    Convert binary data to a line of ASCII characters in base64 coding. The return
-   value is the converted line, including a newline char. The length of *data*
-   should be at most 57 to adhere to the base64 standard.
+   value is the converted line, including a newline char.
+
+   The *base64* encoding for MIME (:rfc:`2045`) requires each encoded line
+   to be no more than 76 characters long (exactly 57 bytes of input data per
+   line). However, other uses of base-64 encoding do not have this limit.
 
 
 .. function:: a2b_qp(string[, header])
@@ -165,7 +168,7 @@
 .. seealso::
 
    Module :mod:`base64`
-      Support for base64 encoding used in MIME email messages.
+      Support for encoding in base 16, 32 and 64.
 
    Module :mod:`binhex`
       Support for the binhex format used on the Macintosh.