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authorRickard Green <[email protected]>2014-03-20 19:01:11 +0100
committerRickard Green <[email protected]>2014-03-21 13:24:40 +0100
commitbf3222f10edbd1f6a5186c8fb35c29900ad0665f (patch)
treefa761309c15de7996634a9474919c9621c126336 /erts/doc/src/erl_nif.xml
parent3c06b5b3cdde72453d97910889e38e91c1dd4870 (diff)
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Introduce minimum allowed major driver and nif versions on load
Diffstat (limited to 'erts/doc/src/erl_nif.xml')
-rw-r--r--erts/doc/src/erl_nif.xml26
1 files changed, 26 insertions, 0 deletions
diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml
index 8b19725c02..6b1f4cccf8 100644
--- a/erts/doc/src/erl_nif.xml
+++ b/erts/doc/src/erl_nif.xml
@@ -316,6 +316,32 @@ ok
<p>The library initialization callbacks <c>load</c>, <c>reload</c> and
<c>upgrade</c> are all thread-safe even for shared state data.</p>
</item>
+
+ <tag><marker id="version_management"/>Version Management</tag>
+ <item><p>
+ When a NIF library is built, information about NIF API version
+ is compiled into the library. When a NIF library is loaded the
+ runtime system verifies that the library is of a compatible version.
+ <c>erl_nif.h</c> defines <c>ERL_NIF_MAJOR_VERSION</c>, and
+ <c>ERL_NIF_MINOR_VERSION</c>. <c>ERL_NIF_MAJOR_VERSION</c> will be
+ incremented when NIF library incompatible changes are made to the
+ Erlang runtime system. Normally it will suffice to recompile the NIF
+ library when the <c>ERL_NIF_MAJOR_VERSION</c> has changed, but it
+ could, under rare circumstances, mean that NIF libraries have to
+ be slightly modified. If so, this will of course be documented.
+ <c>ERL_NIF_MINOR_VERSION</c> will be incremented when
+ new features are added. The runtime system uses the minor version
+ to determine what features to use.
+ </p><p>
+ The runtime system will normally refuse to load a NIF library if
+ the major versions differ, or if the major versions are equal and
+ the minor version used by the NIF library is greater than the one
+ used by the runtime system. Old NIF libraries with lower major
+ versions will however be allowed after a bump of the major version
+ during a transition period of two major releases. Such old NIF
+ libraries might however fail if deprecated features are used.
+ </p></item>
+
<tag>Dirty NIFs</tag>
<item><p><marker id="dirty_nifs"/><em>Note that the dirty NIF functionality
is experimental</em> and that you have to enable support for dirty