diff options
Diffstat (limited to 'lib/stdlib/doc/src/supervisor.xml')
| -rw-r--r-- | lib/stdlib/doc/src/supervisor.xml | 251 |
1 files changed, 126 insertions, 125 deletions
diff --git a/lib/stdlib/doc/src/supervisor.xml b/lib/stdlib/doc/src/supervisor.xml index 45fa0847a8..009aa60faa 100644 --- a/lib/stdlib/doc/src/supervisor.xml +++ b/lib/stdlib/doc/src/supervisor.xml @@ -4,7 +4,7 @@ <erlref> <header> <copyright> - <year>1996</year><year>2010</year> + <year>1996</year><year>2011</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> @@ -83,11 +83,17 @@ supervisor, where all child processes are dynamically added instances of the same process type, i.e. running the same code.</p> - <p>The functions <c>terminate_child/2</c>, <c>delete_child/2</c> + <p>The functions <c>delete_child/2</c> and <c>restart_child/2</c> are invalid for <c>simple_one_for_one</c> supervisors and will return <c>{error,simple_one_for_one}</c> if the specified supervisor uses this restart strategy.</p> + <p>The function <c>terminate_child/2</c> can be used for + children under <c>simple_one_for_one</c> supervisors by + giving the child's <c>pid()</c> as the second argument. If + instead the child specification identifier is used, + <c>terminate_child/2</c> will return + <c>{error,simple_one_for_one}</c>.</p> </item> </list> <p>To prevent a supervisor from getting into an infinite loop of @@ -193,51 +199,81 @@ child_spec() = {Id,StartFunc,Restart,Shutdown,Type,Modules} </item> </list> </section> + <datatypes> + <datatype> + <name name="child"/> + </datatype> + <datatype> + <name name="child_id"/> + <desc><p>Not a <c>pid()</c>.</p></desc> + </datatype> + <datatype> + <name name="child_spec"/> + </datatype> + <datatype> + <name name="mfargs"/> + <desc><p><c>A</c> (the argument list) has the value + <c>undefined</c> if <c>Restart</c> is <c>temporary</c>.</p> + </desc> + </datatype> + <datatype> + <name name="modules"/> + </datatype> + <datatype> + <name name="restart"/> + </datatype> + <datatype> + <name name="shutdown"/> + </datatype> + <datatype> + <name name="strategy"/> + </datatype> + <datatype> + <name name="sup_ref"/> + </datatype> + <datatype> + <name name="worker"/> + </datatype> + </datatypes> <funcs> <func> - <name>start_link(Module, Args) -> Result</name> - <name>start_link(SupName, Module, Args) -> Result</name> + <name name="start_link" arity="2"/> + <name name="start_link" arity="3"/> <fsummary>Create a supervisor process.</fsummary> - <type> - <v>SupName = {local,Name} | {global,Name}</v> - <v> Name = atom()</v> - <v>Module = atom()</v> - <v>Args = term()</v> - <v>Result = {ok,Pid} | ignore | {error,Error}</v> - <v> Pid = pid()</v> - <v> Error = {already_started,Pid}} | shutdown | term()</v> - </type> + <type name="startlink_ret"/> + <type name="startlink_err"/> + <type name="sup_name"/> <desc> <p>Creates a supervisor process as part of a supervision tree. The function will, among other things, ensure that the supervisor is linked to the calling process (its supervisor).</p> - <p>The created supervisor process calls <c>Module:init/1</c> to + <p>The created supervisor process calls <c><anno>Module</anno>:init/1</c> to find out about restart strategy, maximum restart frequency and child processes. To ensure a synchronized start-up procedure, <c>start_link/2,3</c> does not return until - <c>Module:init/1</c> has returned and all child processes + <c><anno>Module</anno>:init/1</c> has returned and all child processes have been started.</p> - <p>If <c>SupName={local,Name}</c> the supervisor is registered + <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>SupName={global,Name}</c> the supervisor is registered + <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> - <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><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> <p>If the supervisor and its child processes are successfully created (i.e. if all child process start functions return <c>{ok,Child}</c>, <c>{ok,Child,Info}</c>, or <c>ignore</c>) the function returns <c>{ok,Pid}</c>, where <c>Pid</c> is the pid of the supervisor. If there already exists a process - with the specified <c>SupName</c> the function returns + with the specified <c><anno>SupName</anno></c> the function returns <c>{error,{already_started,Pid}}</c>, where <c>Pid</c> is the pid of that process.</p> - <p>If <c>Module:init/1</c> returns <c>ignore</c>, this function + <p>If <c><anno>Module</anno>:init/1</c> returns <c>ignore</c>, this function returns <c>ignore</c> as well and the supervisor terminates with reason <c>normal</c>. - If <c>Module:init/1</c> fails or returns an incorrect value, + If <c><anno>Module</anno>:init/1</c> fails or returns an incorrect value, this function returns <c>{error,Term}</c> where <c>Term</c> is a term with information about the error, and the supervisor terminates with reason <c>Term</c>.</p> @@ -249,21 +285,15 @@ child_spec() = {Id,StartFunc,Restart,Shutdown,Type,Modules} </desc> </func> <func> - <name>start_child(SupRef, ChildSpec) -> Result</name> + <name name="start_child" arity="2"/> <fsummary>Dynamically add a child process to a supervisor.</fsummary> - <type> - <v>SupRef = Name | {Name,Node} | {global,Name} | pid()</v> - <v> Name = Node = atom()</v> - <v>ChildSpec = child_spec() | [term()]</v> - <v>Result = {ok,Child} | {ok,Child,Info} | {error,Error}</v> - <v> Child = pid() | undefined</v> - <v> Info = term()</v> - <v> Error = already_present | {already_started,Child} | term()</v> - </type> + <type name="child_spec"/> + <type name="startchild_ret"/> + <type name="startchild_err"/> <desc> <p>Dynamically adds a child specification to the supervisor - <c>SupRef</c> which starts the corresponding child process.</p> - <p><c>SupRef</c> can be:</p> + <c><anno>SupRef</anno></c> which starts the corresponding child process.</p> + <p><marker id="SupRef"><c><anno>SupRef</anno></c></marker> can be:</p> <list type="bulleted"> <item>the pid,</item> <item><c>Name</c>, if the supervisor is locally registered,</item> @@ -272,26 +302,26 @@ child_spec() = {Id,StartFunc,Restart,Shutdown,Type,Modules} <item><c>{global,Name}</c>, if the supervisor is globally registered.</item> </list> - <p><c>ChildSpec</c> should be a valid child specification + <p><c><anno>ChildSpec</anno></c> should be a valid child specification (unless the supervisor is a <c>simple_one_for_one</c> supervisor, see below). The child process will be started by using the start function as defined in the child specification.</p> <p>If the case of a <c>simple_one_for_one</c> supervisor, the child specification defined in <c>Module:init/1</c> will - be used and <c>ChildSpec</c> should instead be an arbitrary - list of terms <c>List</c>. The child process will then be - started by appending <c>List</c> to the existing start + be used and <c><anno>ChildSpec</anno></c> should instead be an arbitrary + list of terms <c><anno>List</anno></c>. The child process will then be + started by appending <c><anno>List</anno></c> to the existing start function arguments, i.e. by calling - <c>apply(M, F, A++List)</c> where <c>{M,F,A}</c> is the start + <c>apply(M, F, A++<anno>List</anno>)</c> where <c>{M,F,A}</c> is the start function defined in the child specification.</p> <p>If there already exists a child specification with - the specified <c>Id</c>, <c>ChildSpec</c> is discarded and + the specified <c><anno>Id</anno></c>, <c><anno>ChildSpec</anno></c> is discarded and the function returns <c>{error,already_present}</c> or - <c>{error,{already_started,Child}}</c>, depending on if + <c>{error,{already_started,<anno>Child</anno>}}</c>, depending on if the corresponding child process is running or not.</p> - <p>If the child process start function returns <c>{ok,Child}</c> - or <c>{ok,Child,Info}</c>, the child specification and pid is + <p>If the child process start function returns <c>{ok,<anno>Child</anno>}</c> + or <c>{ok,<anno>Child</anno>,<anno>Info</anno>}</c>, the child specification and pid is added to the supervisor and the function returns the same value.</p> <p>If the child process start function returns <c>ignore</c>, @@ -306,138 +336,114 @@ child_spec() = {Id,StartFunc,Restart,Shutdown,Type,Modules} </desc> </func> <func> - <name>terminate_child(SupRef, Id) -> Result</name> + <name name="terminate_child" arity="2"/> <fsummary>Terminate a child process belonging to a supervisor.</fsummary> - <type> - <v>SupRef = Name | {Name,Node} | {global,Name} | pid()</v> - <v> Name = Node = atom()</v> - <v>Id = term()</v> - <v>Result = ok | {error,Error}</v> - <v> Error = not_found | simple_one_for_one</v> - </type> <desc> - <p>Tells the supervisor <c>SupRef</c> to terminate the child - process corresponding to the child specification identified - by <c>Id</c>. The process, if there is one, is terminated but - the child specification is kept by the supervisor. This means - that the child process may be later be restarted by - the supervisor. The child process can also be restarted - explicitly by calling <c>restart_child/2</c>. Use - <c>delete_child/2</c> to remove the child specification.</p> - <p>See <c>start_child/2</c> for a description of - <c>SupRef</c>.</p> + <p>Tells the supervisor <c><anno>SupRef</anno></c> to terminate the given + child.</p> + <p>If the supervisor is not <c>simple_one_for_one</c>, + <c><anno>Id</anno></c> must be the child specification identifier. The + process, if there is one, is terminated but the child + specification is kept by the supervisor. The child process + may later be restarted by the supervisor. The child process + can also be restarted explicitly by calling + <c>restart_child/2</c>. Use <c>delete_child/2</c> to remove + the child specification.</p> + <p>If the supervisor is <c>simple_one_for_one</c>, <c><anno>Id</anno></c> + must be the child process' <c>pid()</c>. I the specified + process is alive, but is not a child of the given + supervisor, the function will return + <c>{error,not_found}</c>. If the child specification + identifier is given instead instead of a <c>pid()</c>, the + function will return <c>{error,simple_one_for_one}</c>.</p> <p>If successful, the function returns <c>ok</c>. If there is - no child specification with the specified <c>Id</c>, - the function returns <c>{error,not_found}</c>.</p> + no child specification with the specified <c><anno>Id</anno></c>, the + function returns <c>{error,not_found}</c>.</p> + <p>See <c>start_child/2</c> for a description of + <c><anno>SupRef</anno></c>.</p> </desc> </func> <func> - <name>delete_child(SupRef, Id) -> Result</name> + <name name="delete_child" arity="2"/> <fsummary>Delete a child specification from a supervisor.</fsummary> - <type> - <v>SupRef = Name | {Name,Node} | {global,Name} | pid()</v> - <v> Name = Node = atom()</v> - <v>Id = term()</v> - <v>Result = ok | {error,Error}</v> - <v> Error = running | not_found | simple_one_for_one</v> - </type> <desc> - <p>Tells the supervisor <c>SupRef</c> to delete the child - specification identified by <c>Id</c>. The corresponding child + <p>Tells the supervisor <c><anno>SupRef</anno></c> to delete the child + specification identified by <c><anno>Id</anno></c>. The corresponding child process must not be running, use <c>terminate_child/2</c> to terminate it.</p> - <p>See <c>start_child/2</c> for a description of <c>SupRef</c>.</p> + <p>See <seealso marker="#SupRef"><c>start_child/2</c></seealso> for a description of + <c>SupRef</c>.</p> <p>If successful, the function returns <c>ok</c>. If the child - specification identified by <c>Id</c> exists but + specification identified by <c><anno>Id</anno></c> exists but the corresponding child process is running, the function returns <c>{error,running}</c>. If the child specification - identified by <c>Id</c> does not exist, the function returns + identified by <c><anno>Id</anno></c> does not exist, the function returns <c>{error,not_found}</c>.</p> </desc> </func> <func> - <name>restart_child(SupRef, Id) -> Result</name> + <name name="restart_child" arity="2"/> <fsummary>Restart a terminated child process belonging to a supervisor.</fsummary> - <type> - <v>SupRef = Name | {Name,Node} | {global,Name} | pid()</v> - <v> Name = Node = atom()</v> - <v>Id = term()</v> - <v>Result = {ok,Child} | {ok,Child,Info} | {error,Error}</v> - <v> Child = pid() | undefined</v> - <v> Error = running | not_found | simple_one_for_one | term()</v> - </type> <desc> - <p>Tells the supervisor <c>SupRef</c> to restart a child process + <p>Tells the supervisor <c><anno>SupRef</anno></c> to restart a child process corresponding to the child specification identified by - <c>Id</c>. The child specification must exist and + <c><anno>Id</anno></c>. The child specification must exist and the corresponding child process must not be running.</p> - <p>See <c>start_child/2</c> for a description of <c>SupRef</c>.</p> - <p>If the child specification identified by <c>Id</c> does not + <p>See <seealso marker="#SupRef"><c>start_child/2</c></seealso> for a description of + <c>SupRef</c>.</p> + <p>If the child specification identified by <c><anno>Id</anno></c> does not exist, the function returns <c>{error,not_found}</c>. If the child specification exists but the corresponding process is already running, the function returns <c>{error,running}</c>.</p> - <p>If the child process start function returns <c>{ok,Child}</c> - or <c>{ok,Child,Info}</c>, the pid is added to the supervisor + <p>If the child process start function returns <c>{ok,<anno>Child</anno>}</c> + or <c>{ok,<anno>Child</anno>,<anno>Info</anno>}</c>, the pid is added to the supervisor and the function returns the same value.</p> <p>If the child process start function returns <c>ignore</c>, the pid remains set to <c>undefined</c> and the function returns <c>{ok,undefined}</c>.</p> <p>If the child process start function returns an error tuple or an erroneous value, or if it fails, the function returns - <c>{error,Error}</c> where <c>Error</c> is a term containing + <c>{error,<anno>Error</anno>}</c> where <c><anno>Error</anno></c> is a term containing information about the error.</p> </desc> </func> <func> - <name>which_children(SupRef) -> [{Id,Child,Type,Modules}]</name> + <name name="which_children" arity="1"/> <fsummary>Return information about all children specifications and child processes belonging to a supervisor.</fsummary> - <type> - <v>SupRef = Name | {Name,Node} | {global,Name} | pid()</v> - <v> Name = Node = atom()</v> - <v>Id = term() | undefined</v> - <v>Child = pid() | undefined</v> - <v>Type = worker | supervisor</v> - <v>Modules = [Module] | dynamic</v> - <v> Module = atom()</v> - </type> <desc> <p>Returns a newly created list with information about all child specifications and child processes belonging to - the supervisor <c>SupRef</c>.</p> + the supervisor <c><anno>SupRef</anno></c>.</p> <p>Note that calling this function when supervising a large number of children under low memory conditions can cause an out of memory exception.</p> - <p>See <c>start_child/2</c> for a description of <c>SupRef</c>.</p> + <p>See <seealso marker="#SupRef"><c>start_child/2</c></seealso> for a description of + <c>SupRef</c>.</p> <p>The information given for each child specification/process is:</p> <list type="bulleted"> <item> - <p><c>Id</c> - as defined in the child specification or + <p><c><anno>Id</anno></c> - as defined in the child specification or <c>undefined</c> in the case of a <c>simple_one_for_one</c> supervisor.</p> </item> <item> - <p><c>Child</c> - the pid of the corresponding child + <p><c><anno>Child</anno></c> - the pid of the corresponding child process, or <c>undefined</c> if there is no such process.</p> </item> <item> - <p><c>Type</c> - as defined in the child specification.</p> + <p><c><anno>Type</anno></c> - as defined in the child specification.</p> </item> <item> - <p><c>Modules</c> - as defined in the child specification.</p> + <p><c><anno>Modules</anno></c> - as defined in the child specification.</p> </item> </list> </desc> </func> <func> - <name>count_children(SupRef) -> PropListOfCounts</name> + <name name="count_children" arity="1"/> <fsummary>Return counts for the number of childspecs, active children, supervisors and workers.</fsummary> - <type> - <v>SupRef = Name | {Name,Node} | {global,Name} | pid()</v> - <v> Name = Node = atom()</v> - <v>PropListOfCounts = [{specs, ChildSpecCount}, {active, ActiveProcessCount}, {supervisors, ChildSupervisorCount}, {workers, ChildWorkerCount}]</v> - </type> <desc> <p>Returns a property list (see <c>proplists</c>) containing the counts for each of the following elements of the supervisor's @@ -464,17 +470,12 @@ child_spec() = {Id,StartFunc,Restart,Shutdown,Type,Modules} </desc> </func> <func> - <name>check_childspecs([ChildSpec]) -> Result</name> + <name name="check_childspecs" arity="1"/> <fsummary>Check if children specifications are syntactically correct.</fsummary> - <type> - <v>ChildSpec = child_spec()</v> - <v>Result = ok | {error,Error}</v> - <v> Error = term()</v> - </type> <desc> <p>This function takes a list of child specification as argument and returns <c>ok</c> if all of them are syntactically - correct, or <c>{error,Error}</c> otherwise.</p> + correct, or <c>{error,<anno>Error</anno>}</c> otherwise.</p> </desc> </func> </funcs> @@ -491,9 +492,9 @@ child_spec() = {Id,StartFunc,Restart,Shutdown,Type,Modules} <type> <v>Args = term()</v> <v>Result = {ok,{{RestartStrategy,MaxR,MaxT},[ChildSpec]}} | ignore</v> - <v> RestartStrategy = one_for_all | one_for_one | rest_for_one | simple_one_for_one</v> - <v> MaxR = MaxT = int()>=0</v> - <v> ChildSpec = child_spec()</v> + <v> RestartStrategy = <seealso marker="#type-strategy">strategy()</seealso></v> + <v> MaxR = MaxT = integer()>=0</v> + <v> ChildSpec = <seealso marker="#type-child_spec">child_spec()</seealso></v> </type> <desc> <p>Whenever a supervisor is started using |