Add plugin support for alternative name lookup

OTP behaviour instances (gen_server, gen_fsm, gen_event) can currently
register themselves either locally or globally, and the behaviour
libraries (including gen.erl) support both addressing methods, as well
as the normal Pid and {Name, Node}.

However, there are alternative registry implementations - e.g. gproc -
and one can well imagine other ways of locating a behaviour instance,
e.g. on a node connected only via a TCP tunnel, rather than via
Distributed Erlang. In all these cases, one needs to write extra code
to identify the behaviour instance, even though the instance itself
need not be aware of how it is located.

This patch introduces a new way of locating a behaviour instance:
{via, Module, Name}.

Module is expected to export a subset of the functions in global.erl,
namely:

register_name(Name, Pid) -> yes | no
whereis_name(Name)  -> pid() | undefined
unregister_name(Name) -> ok
send(Name, Msg) -> Pid

Semantics are expected to be the same as for global.erl

This can be used in all places where {global, Name} is accepted.

faulty export in gen_fsm_SUITE.erl

await process death in dummy_via:reset()

fix error in gen_[server|fsm]:enter_loop()

fix documentation

5 files changed, 126 insertions, 48 deletions

diff --git a/lib/stdlib/doc/src/gen_event.xml b/lib/stdlib/doc/src/gen_event.xml
index 24bcb419fe..0f50b37de6 100644
--- a/lib/stdlib/doc/src/gen_event.xml
+++ b/lib/stdlib/doc/src/gen_event.xml
@@ -120,8 +120,10 @@ gen_event:stop             ----->  Module:terminate/2
       <name>start_link(EventMgrName) -> Result</name>
       <fsummary>Create a generic event manager process in a supervision tree.</fsummary>
       <type>
-        <v>EventMgrName = {local,Name} | {global,Name}</v>
+        <v>EventMgrName = {local,Name} | {global,GlobalName}
+	| {via,Module,ViaName}</v>
         <v>&nbsp;Name = atom()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Result = {ok,Pid} | {error,{already_started,Pid}}</v>
         <v>&nbsp;Pid = pid()</v>
       </type>
@@ -132,10 +134,17 @@ gen_event:stop             ----->  Module:terminate/2
           the event manager is linked to the supervisor.</p>
         <p>If <c>EventMgrName={local,Name}</c>, the event manager is
           registered locally as <c>Name</c> using <c>register/2</c>.
-          If <c>EventMgrName={global,Name}</c>, the event manager is
-          registered globally as <c>Name</c> using
+          If <c>EventMgrName={global,GlobalName}</c>, the event manager is
+          registered globally as <c>GlobalName</c> using
           <c>global:register_name/2</c>. If no name is provided,
-          the event manager is not registered.</p>
+          the event manager is not registered.
+	If <c>EventMgrName={via,Module,ViaName}</c>, the event manager will
+	register with the registry represented by <c>Module</c>.
+	The <c>Module</c> callback should export the functions
+	<c>register_name/2</c>, <c>unregister_name/1</c>,
+	<c>whereis_name/1</c> and <c>send/2</c>, which should behave like the
+	corresponding functions in <c>global</c>. Thus,
+	<c>{via,global,GlobalName}</c> is a valid reference.</p>
         <p>If the event manager is successfully created the function
           returns <c>{ok,Pid}</c>, where <c>Pid</c> is the pid of
           the event manager. If there already exists a process with
@@ -149,8 +158,10 @@ gen_event:stop             ----->  Module:terminate/2
       <name>start(EventMgrName) -> Result</name>
       <fsummary>Create a stand-alone event manager process.</fsummary>
       <type>
-        <v>EventMgrName = {local,Name} | {global,Name}</v>
+        <v>EventMgrName = {local,Name} | {global,GlobalName}
+	| {via,Module,ViaName}</v>
         <v>&nbsp;Name = atom()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Result = {ok,Pid} | {error,{already_started,Pid}}</v>
         <v>&nbsp;Pid = pid()</v>
       </type>
@@ -166,8 +177,10 @@ gen_event:stop             ----->  Module:terminate/2
       <name>add_handler(EventMgrRef, Handler, Args) -> Result</name>
       <fsummary>Add an event handler to a generic event manager.</fsummary>
       <type>
-        <v>EventMgr = Name | {Name,Node} | {global,Name} | pid()</v>
+        <v>EventMgr = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>&nbsp;Name = Node = atom()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Handler = Module | {Module,Id}</v>
         <v>&nbsp;Module = atom()</v>
         <v>&nbsp;Id = term()</v>
@@ -185,8 +198,10 @@ gen_event:stop             ----->  Module:terminate/2
           <item><c>Name</c>, if the event manager is locally registered,</item>
           <item><c>{Name,Node}</c>, if the event manager is locally
            registered at another node, or</item>
-          <item><c>{global,Name}</c>, if the event manager is globally
+          <item><c>{global,GlobalName}</c>, if the event manager is globally
            registered.</item>
+	   <item><c>{via,Module,ViaName}</c>, if the event manager is registered
+	   through an alternative process registry.</item>
         </list>
         <p><c>Handler</c> is the name of the callback module <c>Module</c> or
           a tuple <c>{Module,Id}</c>, where <c>Id</c> is any term.
@@ -207,8 +222,10 @@ gen_event:stop             ----->  Module:terminate/2
       <name>add_sup_handler(EventMgrRef, Handler, Args) -> Result</name>
       <fsummary>Add a supervised event handler to a generic event manager.</fsummary>
       <type>
-        <v>EventMgr = Name | {Name,Node} | {global,Name} | pid()</v>
+        <v>EventMgr = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>&nbsp;Name = Node = atom()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Handler = Module | {Module,Id}</v>
         <v>&nbsp;Module = atom()</v>
         <v>&nbsp;Id = term()</v>
@@ -252,8 +269,10 @@ gen_event:stop             ----->  Module:terminate/2
       <name>sync_notify(EventMgrRef, Event) -> ok</name>
       <fsummary>Notify an event manager about an event.</fsummary>
       <type>
-        <v>EventMgrRef = Name | {Name,Node} | {global,Name} | pid()</v>
+        <v>EventMgrRef = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>&nbsp;Name = Node = atom()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Event = term()</v>
       </type>
       <desc>
@@ -277,8 +296,10 @@ gen_event:stop             ----->  Module:terminate/2
       <name>call(EventMgrRef, Handler, Request, Timeout) -> Result</name>
       <fsummary>Make a synchronous call to a generic event manager.</fsummary>
       <type>
-        <v>EventMgrRef = Name | {Name,Node} | {global,Name} | pid()</v>
+        <v>EventMgrRef = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>&nbsp;Name = Node = atom()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Handler = Module | {Module,Id}</v>
         <v>&nbsp;Module = atom()</v>
         <v>&nbsp;Id = term()</v>
@@ -317,8 +338,10 @@ gen_event:stop             ----->  Module:terminate/2
       <name>delete_handler(EventMgrRef, Handler, Args) -> Result</name>
       <fsummary>Delete an event handler from a generic event manager.</fsummary>
       <type>
-        <v>EventMgrRef = Name | {Name,Node} | {global,Name} | pid()</v>
+        <v>EventMgrRef = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>&nbsp;Name = Node = atom()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Handler = Module | {Module,Id}</v>
         <v>&nbsp;Module = atom()</v>
         <v>&nbsp;Id = term()</v>
@@ -345,8 +368,10 @@ gen_event:stop             ----->  Module:terminate/2
       <name>swap_handler(EventMgrRef, {Handler1,Args1}, {Handler2,Args2}) -> Result</name>
       <fsummary>Replace an event handler in a generic event manager.</fsummary>
       <type>
-        <v>EventMgrRef = Name | {Name,Node} | {global,Name} | pid()</v>
+        <v>EventMgrRef = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>&nbsp;Name = Node = atom()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Handler1 = Handler2 = Module | {Module,Id}</v>
         <v>&nbsp;Module = atom()</v>
         <v>&nbsp;Id = term()</v>
@@ -389,8 +414,10 @@ gen_event:stop             ----->  Module:terminate/2
       <name>swap_sup_handler(EventMgrRef, {Handler1,Args1}, {Handler2,Args2}) -> Result</name>
       <fsummary>Replace an event handler in a generic event manager.</fsummary>
       <type>
-        <v>EventMgrRef = Name | {Name,Node} | {global,Name} | pid()</v>
+        <v>EventMgrRef = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>&nbsp;Name = Node = atom()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Handler1 = Handler 2 = Module | {Module,Id}</v>
         <v>&nbsp;Module = atom()</v>
         <v>&nbsp;Id = term()</v>
@@ -411,8 +438,10 @@ gen_event:stop             ----->  Module:terminate/2
       <name>which_handlers(EventMgrRef) -> [Handler]</name>
       <fsummary>Return all event handlers installed in a generic event manager.</fsummary>
       <type>
-        <v>EventMgrRef = Name | {Name,Node} | {global,Name} | pid()</v>
+        <v>EventMgrRef = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>&nbsp;Name = Node = atom()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Handler = Module | {Module,Id}</v>
         <v>&nbsp;Module = atom()</v>
         <v>&nbsp;Id = term()</v>
@@ -428,8 +457,10 @@ gen_event:stop             ----->  Module:terminate/2
       <name>stop(EventMgrRef) -> ok</name>
       <fsummary>Terminate a generic event manager.</fsummary>
       <type>
-        <v>EventMgrRef = Name | {Name,Node} | {global,Name} | pid()</v>
+        <v>EventMgrRef = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>Name = Node = atom()</v>
+        <v>GlobalName = ViaName = term()</v>
       </type>
       <desc>
         <p>Terminates the event manager <c>EventMgrRef</c>. Before
diff --git a/lib/stdlib/doc/src/gen_fsm.xml b/lib/stdlib/doc/src/gen_fsm.xml
index 421eeb4fd3..73c1911f1e 100644
--- a/lib/stdlib/doc/src/gen_fsm.xml
+++ b/lib/stdlib/doc/src/gen_fsm.xml
@@ -84,9 +84,10 @@ gen_fsm:sync_send_all_state_event -----> Module:handle_sync_event/4
       <name>start_link(FsmName, Module, Args, Options) -> Result</name>
       <fsummary>Create a gen_fsm process in a supervision tree.</fsummary>
       <type>
-        <v>FsmName = {local,Name} | {global,GlobalName}</v>
+        <v>FsmName = {local,Name} | {global,GlobalName}
+	| {via,Module,ViaName}</v>
         <v>&nbsp;Name = atom()</v>
-        <v>&nbsp;GlobalName = term()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Module = atom()</v>
         <v>Args = term()</v>
         <v>Options = [Option]</v>
@@ -113,8 +114,16 @@ gen_fsm:sync_send_all_state_event -----> Module:handle_sync_event/4
           locally as <c>Name</c> using <c>register/2</c>.
           If <c>FsmName={global,GlobalName}</c>, the gen_fsm is
           registered globally as <c>GlobalName</c> using
-          <c>global:register_name/2</c>. If no name is provided,
-          the gen_fsm is not registered.</p>
+          <c>global:register_name/2</c>.
+	  If <c>EventMgrName={via,Module,ViaName}</c>, the event manager will
+	  register with the registry represented by <c>Module</c>.
+	  The <c>Module</c> callback should export the functions
+	  <c>register_name/2</c>, <c>unregister_name/1</c>,
+	  <c>whereis_name/1</c> and <c>send/2</c>, which should behave like the
+	  corresponding functions in <c>global</c>. Thus,
+	<c>{via,global,GlobalName}</c> is a valid reference.</p>
+	<p>If no name is provided,
+	the gen_fsm is not registered.</p>
         <p><c>Module</c> is the name of the callback module.</p>
         <p><c>Args</c> is an arbitrary term which is passed as
           the argument to <c>Module:init/1</c>.</p>
@@ -154,9 +163,10 @@ gen_fsm:sync_send_all_state_event -----> Module:handle_sync_event/4
       <name>start(FsmName, Module, Args, Options) -> Result</name>
       <fsummary>Create a stand-alone gen_fsm process.</fsummary>
       <type>
-        <v>FsmName = {local,Name} | {global,GlobalName}</v>
+        <v>FsmName = {local,Name} | {global,GlobalName}
+	| {via,Module,ViaName}</v>
         <v>&nbsp;Name = atom()</v>
-        <v>&nbsp;GlobalName = term()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Module = atom()</v>
         <v>Args = term()</v>
         <v>Options = [Option]</v>
@@ -180,9 +190,10 @@ gen_fsm:sync_send_all_state_event -----> Module:handle_sync_event/4
       <name>send_event(FsmRef, Event) -> ok</name>
       <fsummary>Send an event asynchronously to a generic FSM.</fsummary>
       <type>
-        <v>FsmRef = Name | {Name,Node} | {global,GlobalName} | pid()</v>
+        <v>FsmRef = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>&nbsp;Name = Node = atom()</v>
-        <v>&nbsp;GlobalName = term()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Event = term()</v>
       </type>
       <desc>
@@ -196,9 +207,11 @@ gen_fsm:sync_send_all_state_event -----> Module:handle_sync_event/4
           <item>the pid,</item>
           <item><c>Name</c>, if the gen_fsm is locally registered,</item>
           <item><c>{Name,Node}</c>, if the gen_fsm is locally
-           registered at another node, or</item>
-          <item><c>{global,GlobalName}</c>, if the gen_fsm is globally
-           registered.</item>
+	  registered at another node, or</item>
+	  <item><c>{global,GlobalName}</c>, if the gen_fsm is globally
+	  registered.</item>
+	  <item><c>{via,Module,ViaName}</c>, if the event manager is registered
+	  through an alternative process registry.</item>
         </list>
         <p><c>Event</c> is an arbitrary term which is passed as one of
           the arguments to <c>Module:StateName/2</c>.</p>
@@ -208,9 +221,10 @@ gen_fsm:sync_send_all_state_event -----> Module:handle_sync_event/4
       <name>send_all_state_event(FsmRef, Event) -> ok</name>
       <fsummary>Send an event asynchronously to a generic FSM.</fsummary>
       <type>
-        <v>FsmRef = Name | {Name,Node} | {global,GlobalName} | pid()</v>
+        <v>FsmRef = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>&nbsp;Name = Node = atom()</v>
-        <v>&nbsp;GlobalName = term()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Event = term()</v>
       </type>
       <desc>
@@ -232,9 +246,10 @@ gen_fsm:sync_send_all_state_event -----> Module:handle_sync_event/4
       <name>sync_send_event(FsmRef, Event, Timeout) -> Reply</name>
       <fsummary>Send an event synchronously to a generic FSM.</fsummary>
       <type>
-        <v>FsmRef = Name | {Name,Node} | {global,GlobalName} | pid()</v>
+        <v>FsmRef = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>&nbsp;Name = Node = atom()</v>
-        <v>&nbsp;GlobalName = term()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Event = term()</v>
         <v>Timeout = int()>0 | infinity</v>
         <v>Reply = term()</v>
@@ -264,9 +279,10 @@ gen_fsm:sync_send_all_state_event -----> Module:handle_sync_event/4
       <name>sync_send_all_state_event(FsmRef, Event, Timeout) -> Reply</name>
       <fsummary>Send an event synchronously to a generic FSM.</fsummary>
       <type>
-        <v>FsmRef = Name | {Name,Node} | {global,GlobalName} | pid()</v>
+        <v>FsmRef = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>&nbsp;Name = Node = atom()</v>
-        <v>&nbsp;GlobalName = term()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Event = term()</v>
         <v>Timeout = int()>0 | infinity</v>
         <v>Reply = term()</v>
@@ -388,9 +404,10 @@ gen_fsm:sync_send_all_state_event -----> Module:handle_sync_event/4
         <v>&nbsp;&nbsp;&nbsp;&nbsp;| {log_to_file,FileName} | {install,{Func,FuncState}}</v>
         <v>StateName = atom()</v>
         <v>StateData = term()</v>
-        <v>FsmName = {local,Name} | {global,GlobalName}</v>
+        <v>FsmName = {local,Name} | {global,GlobalName}
+	| {via,Module,ViaName}</v>
         <v>&nbsp;Name = atom()</v>
-        <v>&nbsp;GlobalName = term()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Timeout = int() | infinity</v>
       </type>
       <desc>
diff --git a/lib/stdlib/doc/src/gen_server.xml b/lib/stdlib/doc/src/gen_server.xml
index 1045766e01..90b77d5cb6 100644
--- a/lib/stdlib/doc/src/gen_server.xml
+++ b/lib/stdlib/doc/src/gen_server.xml
@@ -83,9 +83,10 @@ gen_server:abcast     -----> Module:handle_cast/2
       <name>start_link(ServerName, Module, Args, Options) -> Result</name>
       <fsummary>Create a gen_server process in a supervision tree.</fsummary>
       <type>
-        <v>ServerName = {local,Name} | {global,GlobalName}</v>
+        <v>ServerName = {local,Name} | {global,GlobalName}
+	| {via,Module,ViaName}</v>
         <v>&nbsp;Name = atom()</v>
-        <v>&nbsp;GlobalName = term()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Module = atom()</v>
         <v>Args = term()</v>
         <v>Options = [Option]</v>
@@ -111,14 +112,22 @@ gen_server:abcast     -----> Module:handle_cast/2
           If <c>ServerName={global,GlobalName}</c> the gen_server is
           registered globally as <c>GlobalName</c> using
           <c>global:register_name/2</c>. If no name is provided,
-          the gen_server is not registered.</p>
+          the gen_server is not registered.
+	  If <c>EventMgrName={via,Module,ViaName}</c>, the event manager will
+	  register with the registry represented by <c>Module</c>.
+	  The <c>Module</c> callback should export the functions
+	  <c>register_name/2</c>, <c>unregister_name/1</c>,
+	  <c>whereis_name/1</c> and <c>send/2</c>, which should behave like the
+	  corresponding functions in <c>global</c>. Thus,
+	<c>{via,global,GlobalName}</c> is a valid reference.</p>
         <p><c>Module</c> is the name of the callback module.</p>
         <p><c>Args</c> is an arbitrary term which is passed as
           the argument to <c>Module:init/1</c>.</p>
         <p>If the option <c>{timeout,Time}</c> is present,
           the gen_server is allowed to spend <c>Time</c> milliseconds
           initializing or it will be terminated and the start function
-          will return <c>{error,timeout}</c>.</p>
+          will return <c>{error,timeout}</c>.
+	</p>
         <p>If the option <c>{debug,Dbgs}</c> is present,
           the corresponding <c>sys</c> function will be called for each
           item in <c>Dbgs</c>. See
@@ -151,9 +160,10 @@ gen_server:abcast     -----> Module:handle_cast/2
       <name>start(ServerName, Module, Args, Options) -> Result</name>
       <fsummary>Create a stand-alone gen_server process.</fsummary>
       <type>
-        <v>ServerName = {local,Name} | {global,GlobalName}</v>
+        <v>ServerName = {local,Name} | {global,GlobalName}
+	| {via,Module,ViaName}</v>
         <v>&nbsp;Name = atom()</v>
-        <v>&nbsp;GlobalName = term()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Module = atom()</v>
         <v>Args = term()</v>
         <v>Options = [Option]</v>
@@ -178,9 +188,10 @@ gen_server:abcast     -----> Module:handle_cast/2
       <name>call(ServerRef, Request, Timeout) -> Reply</name>
       <fsummary>Make a synchronous call to a generic server.</fsummary>
       <type>
-        <v>ServerRef = Name | {Name,Node} | {global,GlobalName} | pid()</v>
+        <v>ServerRef = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>&nbsp;Node = atom()</v>
-        <v>&nbsp;GlobalName = term()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Request = term()</v>
         <v>Timeout = int()>0 | infinity</v>
         <v>Reply = term()</v>
@@ -198,6 +209,8 @@ gen_server:abcast     -----> Module:handle_cast/2
            registered at another node, or</item>
           <item><c>{global,GlobalName}</c>, if the gen_server is
            globally registered.</item>
+          <item><c>{via,Module,ViaName}</c>, if the gen_server is
+           registered through an alternative process registry.</item>
         </list>
         <p><c>Request</c> is an arbitrary term which is passed as one of
           the arguments to <c>Module:handle_call/3</c>.</p>
@@ -281,9 +294,10 @@ gen_server:abcast     -----> Module:handle_cast/2
       <name>cast(ServerRef, Request) -> ok</name>
       <fsummary>Send an asynchronous request to a generic server.</fsummary>
       <type>
-        <v>ServerRef = Name | {Name,Node} | {global,GlobalName} | pid()</v>
+        <v>ServerRef = Name | {Name,Node} | {global,GlobalName}
+	| {via,Module,ViaName} | pid()</v>
         <v>&nbsp;Node = atom()</v>
-        <v>&nbsp;GlobalName = term()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Request = term()</v>
       </type>
       <desc>
@@ -355,9 +369,10 @@ gen_server:abcast     -----> Module:handle_cast/2
         <v>&nbsp;&nbsp;&nbsp;Dbg = trace | log | statistics</v>
         <v>&nbsp;&nbsp;&nbsp;&nbsp;| {log_to_file,FileName} | {install,{Func,FuncState}}</v>
         <v>State = term()</v>
-        <v>ServerName = {local,Name} | {global,GlobalName}</v>
+        <v>ServerName = {local,Name} | {global,GlobalName}
+	| {via,Module,ViaName}</v>
         <v>&nbsp;Name = atom()</v>
-        <v>&nbsp;GlobalName = term()</v>
+        <v>&nbsp;GlobalName = ViaName = term()</v>
         <v>Timeout = int() | infinity</v>
       </type>
       <desc>
diff --git a/lib/stdlib/doc/src/supervisor.xml b/lib/stdlib/doc/src/supervisor.xml
index cddb55e5c5..73df7183e6 100644
--- a/lib/stdlib/doc/src/supervisor.xml
+++ b/lib/stdlib/doc/src/supervisor.xml
@@ -271,8 +271,14 @@ child_spec() = {Id,StartFunc,Restart,Shutdown,Type,Modules}
         <p>If <c><anno>SupName</anno>={local,Name}</c> the supervisor is registered
           locally as <c>Name</c> using <c>register/2</c>. If
           <c><anno>SupName</anno>={global,Name}</c> the supervisor is registered
-          globally as <c>Name</c> using <c>global:register_name/2</c>.
-          If no name is provided, the supervisor is not registered.</p>
+          globally as <c>Name</c> using <c>global:register_name/2</c>. If
+          <c><anno>SupName</anno>={via,Module,Name}</c> the supervisor
+	  is registered as <c>Name</c> using the registry represented by
+	  <c>Module</c>. The <c>Module</c> callback should export the functions
+	  <c>register_name/2</c>, <c>unregister_name/1</c> and <c>send/2</c>,
+	  which should behave like the corresponding functions in <c>global</c>.
+	  Thus, <c>{via,global,Name}</c> is a valid reference.</p>
+          <p>If no name is provided, the supervisor is not registered.</p>
         <p><c><anno>Module</anno></c> is the name of the callback module.</p>
         <p><c><anno>Args</anno></c> is an arbitrary term which is passed as
           the argument to <c><anno>Module</anno>:init/1</c>.</p>
@@ -315,6 +321,8 @@ child_spec() = {Id,StartFunc,Restart,Shutdown,Type,Modules}
            registered at another node, or</item>
           <item><c>{global,Name}</c>, if the supervisor is globally
            registered.</item>
+          <item><c>{via,Module,Name}</c>, if the supervisor is registered
+	  through an alternative process registry.</item>
         </list>
         <p><c><anno>ChildSpec</anno></c> should be a valid child specification
           (unless the supervisor is a <c>simple_one_for_one</c>
diff --git a/lib/stdlib/doc/src/supervisor_bridge.xml b/lib/stdlib/doc/src/supervisor_bridge.xml
index c1a5e7947f..f6712d6c1d 100644
--- a/lib/stdlib/doc/src/supervisor_bridge.xml
+++ b/lib/stdlib/doc/src/supervisor_bridge.xml
@@ -63,6 +63,13 @@
           If <c><anno>SupBridgeName</anno>={global,<anno>Name</anno>}</c> the supervisor_bridge is
           registered globally as <c><anno>Name</anno></c> using
           <c>global:register_name/2</c>.
+          If <c><anno>SupBridgeName</anno>={via,<anno>Module</anno>,<anno>Name</anno>}</c> the supervisor_bridge is
+          registered as <c><anno>Name</anno></c> using a registry represented
+	  by <anno>Module</anno>. The <c>Module</c> callback should export
+	  the functions <c>register_name/2</c>, <c>unregister_name/1</c>
+	  and <c>send/2</c>, which should behave like the
+	  corresponding functions in <c>global</c>. Thus,
+	  <c>{via,global,GlobalName}</c> is a valid reference.
           If no name is provided, the supervisor_bridge is not registered.
           If there already exists a process with the specified
           <c><anno>SupBridgeName</anno></c> the function returns