File 0312-erlang-module-doc-binary_to_existing_atom.... of Package erlang

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File 0312-erlang-module-doc-binary_to_existing_atom.patch of Package erlang (Revision fcc54f6733a70ae4c018943d955238fa)

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From ae7278e494f6d0cff4c490c51e371fa343c2887d Mon Sep 17 00:00:00 2001
From: Kjell Winblad <kjellwinblad@gmail.com>
Date: Tue, 1 Sep 2020 14:12:46 +0200
Subject: [PATCH 12/39] erlang module doc: binary_to_existing_atom

* Define what it means for an atom to exist
* Describe the purpose of the function
* Note about atom max length
---
 erts/doc/src/erlang.xml | 31 ++++++++++++++++++++++++++++---
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/erts/doc/src/erlang.xml b/erts/doc/src/erlang.xml
index 0633dd6f15..a33eaffb87 100644
--- a/erts/doc/src/erlang.xml
+++ b/erts/doc/src/erlang.xml
@@ -535,6 +535,25 @@ Z = erlang:adler32_combine(X,Y,iolist_size(Data2)).</code>
 but the atom must exist. An atom exists if it has
 been created by the run-time system by either loading code or creating
 a term in which the atom is part.
+
+ The Erlang system has a <seeguide
+ marker="system/efficiency_guide:advanced">configurable
+ limit</seeguide> for the total number of atoms that can exist,
+ and atoms are not garbage collected. Therefore, it is not safe
+ to create many atoms from binaries that come from an untrusted
+ source (for example, a file fetched from the Internet), for
+ example, using <seemfa
+ marker="#binary_to_atom/2"><c>binary_to_atom/2</c></seemfa>. This
+ function is thus the appropriate option when the input binary
+ comes from an untrusted source.
+
+ An atom exists in an Erlang system when included in a
+ loaded Erlang module or when created programmatically (for
+ example, by <c>binary_to_atom/2</c>). See the next note for an
+ example of when an atom exists in the source code for an
+ Erlang module but not in the compiled version of the same
+ module.
+
 Failure: <c>badarg</c> if the atom does not exist.
 	<note>
 	 Note that the compiler may optimize away atoms. For
@@ -546,6 +565,12 @@ Z = erlang:adler32_combine(X,Y,iolist_size(Data2)).</code>
 	 to <c>binary_to_existing_atom(&lt;&lt;"some_atom"&gt;&gt;, utf8)</c>
 	 will fail.
 	</note>
+ <note>
+ The number of characters that are permitted in an atom
+ name is limited. The default limits can be found in the
+ <seeguide marker="system/efficiency_guide:advanced">
+ efficiency guide (section Advanced)</seeguide>.
+ </note>
 </desc>
 </func>
 
-- 
2.26.2

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File 0312-erlang-module-doc-binary_to_existing_atom.patch of Package erlang (Revision fcc54f6733a70ae4c018943d955238fa)

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