diff options
Diffstat (limited to 'erts/doc/src/erl_nif.xml')
| -rw-r--r-- | erts/doc/src/erl_nif.xml | 90 |
1 files changed, 83 insertions, 7 deletions
diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml index 5cbeddabd9..d58ebd3171 100644 --- a/erts/doc/src/erl_nif.xml +++ b/erts/doc/src/erl_nif.xml @@ -2217,6 +2217,18 @@ enif_inspect_iovec(env, max_elements, term, &tail, &iovec); </func> <func> + <name since="OTP @OTP-15362@"><ret>ERL_NIF_TERM</ret> + <nametext>enif_make_monitor_term(ErlNifEnv* env, const ErlNifMonitor* mon)</nametext></name> + <fsummary>Make monitor term from the given monitor identifier.</fsummary> + <desc> + <p>Creates a term identifying the given monitor received from + <seealso marker="#enif_monitor_process"><c>enif_monitor_process</c> + </seealso>.</p> + <p>This function is primarily intended for debugging purpose.</p> + </desc> + </func> + + <func> <name since="OTP R14B"><ret>unsigned char *</ret><nametext>enif_make_new_binary(ErlNifEnv* env, size_t size, ERL_NIF_TERM* termp)</nametext></name> <fsummary>Allocate and create a new binary term.</fsummary> @@ -3056,12 +3068,18 @@ enif_map_iterator_destroy(env, &iter);</code> <p>Argument <c>mode</c> describes the type of events to wait for. It can be <c>ERL_NIF_SELECT_READ</c>, <c>ERL_NIF_SELECT_WRITE</c> or a bitwise OR combination to wait for both. It can also be <c>ERL_NIF_SELECT_STOP</c> - which is described further below. When a read or write event is triggered, + or <c>ERL_NIF_SELECT_CANCEL</c> which are described further + below. When a read or write event is triggered, a notification message like this is sent to the process identified by <c>pid</c>:</p> <code type="none">{select, Obj, Ref, ready_input | ready_output}</code> <p><c>ready_input</c> or <c>ready_output</c> indicates if the event object is ready for reading or writing.</p> + <note><p>For complete control over the message format use the newer functions + <seealso marker="#enif_select_read"><c>enif_select_read</c></seealso> or + <seealso marker="#enif_select_write"><c>enif_select_write</c></seealso> + introduced in erts-11.0 (OTP-22.0).</p> + </note> <p>Argument <c>pid</c> may be <c>NULL</c> to indicate the calling process.</p> <p>Argument <c>obj</c> is a resource object obtained from <seealso marker="#enif_alloc_resource"><c>enif_alloc_resource</c></seealso>. @@ -3073,17 +3091,29 @@ enif_map_iterator_destroy(env, &iter);</code> or the atom <c>undefined</c>. It will be passed as <c>Ref</c> in the notifications. If a selective <c>receive</c> statement is used to wait for the notification then a reference created just before the <c>receive</c> will exploit a runtime - optimization that bypasses all earlier received messages in the queue.</p> + optimization that bypasses all earlier received messages in the + queue.</p> <p>The notifications are one-shot only. To receive further notifications of the same type (read or write), repeated calls to <c>enif_select</c> must be made after receiving each notification.</p> + <p><c>ERL_NIF_SELECT_CANCEL</c> can be used to cancel previously + selected events. It must be used in a bitwise OR combination with + <c>ERL_NIF_SELECT_READ</c> and/or <c>ERL_NIF_SELECT_WRITE</c> to + indicate which type of event to cancel. Arguments <c>pid</c> and + <c>ref</c> are ignored when <c>ERL_NIF_SELECT_CANCEL</c> is specified. + The return value will tell if the event was actualy cancelled or if a + notification may already have been sent.</p> <p>Use <c>ERL_NIF_SELECT_STOP</c> as <c>mode</c> in order to safely close an event object that has been passed to <c>enif_select</c>. The <seealso marker="#ErlNifResourceStop"><c>stop</c></seealso> callback of the resource <c>obj</c> will be called when it is safe to close the event object. This safe way of closing event objects must be used - even if all notifications have been received and no further calls to - <c>enif_select</c> have been made.</p> + even if all notifications have been received (or cancelled) and no + further calls to <c>enif_select</c> have been made. + <c>ERL_NIF_SELECT_STOP</c> will first cancel any selected events + before it calls or schedules the <c>stop</c> callback. Arguments + <c>pid</c> and <c>ref</c> are ignored when <c>ERL_NIF_SELECT_STOP</c> + is specified.</p> <p>The first call to <c>enif_select</c> for a specific OS <c>event</c> will establish a relation between the event object and the containing resource. All subsequent calls for an <c>event</c> must pass its containing resource as argument @@ -3105,7 +3135,15 @@ enif_map_iterator_destroy(env, &iter);</code> <item>The stop callback was called directly by <c>enif_select</c>.</item> <tag><c>ERL_NIF_SELECT_STOP_SCHEDULED</c></tag> <item>The stop callback was scheduled to run on some other thread - or later by this thread.</item> + or later by this thread.</item> + <tag><c>ERL_NIF_SELECT_READ_CANCELLED</c></tag> + <item>A read event was cancelled by <c>ERL_NIF_SELECT_CANCEL</c> or + <c>ERL_NIF_SELECT_STOP</c> and is guaranteed not to generate a + <c>ready_input</c> notification message.</item> + <tag><c>ERL_NIF_SELECT_WRITE_CANCELLED</c></tag> + <item>A write event was cancelled by <c>ERL_NIF_SELECT_CANCEL</c> or + <c>ERL_NIF_SELECT_STOP</c> and is guaranteed not to generate a + <c>ready_output</c> notification message.</item> </taglist> <p>Returns a negative value if the call failed where the following bits can be set:</p> <taglist> @@ -3131,6 +3169,43 @@ if (retval & ERL_NIF_SELECT_STOP_CALLED) { } </code> </note> + <note><p>The mode flag <c>ERL_NIF_SELECT_CANCEL</c> and the return flags + <c>ERL_NIF_SELECT_READ_CANCELLED</c> and + <c>ERL_NIF_SELECT_WRITE_CANCELLED</c> were introduced in erts-11.0 + (OTP-22.0).</p> + </note> + </desc> + </func> + + <func> + <name since="OTP 22.0"><ret>int</ret> + <nametext>enif_select_read(ErlNifEnv* env, ErlNifEvent event, void* obj, + const ErlNifPid* pid, ERL_NIF_TERM msg, ErlNifEnv* msg_env)</nametext> + </name> + <name since="OTP 22.0"><ret>int</ret> + <nametext>enif_select_write(ErlNifEnv* env, ErlNifEvent event, void* obj, + const ErlNifPid* pid, ERL_NIF_TERM msg, ErlNifEnv* msg_env)</nametext> + </name> + <fsummary>Manage subscription on IO event.</fsummary> + <desc> + <p>These are variants of <seealso marker="#enif_select">enif_select</seealso> + where you can supply your own message term <c>msg</c> that will be sent to + the process instead of the predefined tuple <c>{select,_,_,_}.</c></p> + <p>Argument <c>msg_env</c> must either be <c>NULL</c> or the environment of + <c>msg</c> allocated with <seealso marker="#enif_alloc_env"> + <c>enif_alloc_env</c></seealso>. If argument <c>msg_env</c> is + <c>NULL</c> the term <c>msg</c> will be copied, otherwise both + <c>msg</c> and <c>msg_env</c> will be invalidated by a successful call + to <c>enif_select_read</c> or <c>enif_select_write</c>. The environment + is then to either be freed with <seealso marker="#enif_free_env"> + <c>enif_free_env</c></seealso> or cleared for reuse with + <seealso marker="#enif_clear_env"><c>enif_clear_env</c></seealso>. An + unsuccessful call will leave <c>msg</c> and <c>msg_env</c> still valid.</p> + <p>Apart from the message format <c>enif_select_read</c> and + <c>enif_select_write</c> behaves exactly the same as <seealso + marker="#enif_select">enif_select</seealso> with argument <c>mode</c> as + either <c>ERL_NIF_SELECT_READ</c> or <c>ERL_NIF_SELECT_WRITE</c>. To + cancel or close events use <seealso marker="#enif_select">enif_select</seealso>.</p> </desc> </func> @@ -3179,8 +3254,9 @@ if (retval & ERL_NIF_SELECT_STOP_CALLED) { <c>msg</c>) is invalidated by a successful call to <c>enif_send</c>. The environment is to either be freed with <seealso marker="#enif_free_env"> - <c>enif_free_env</c></seealso> of cleared for reuse with - <seealso marker="#enif_clear_env"><c>enif_clear_env</c></seealso>.</p> + <c>enif_free_env</c></seealso> or cleared for reuse with + <seealso marker="#enif_clear_env"><c>enif_clear_env</c></seealso>. An + unsuccessful call will leave <c>msg</c> and <c>msg_env</c> still valid.</p> <p>If <c>msg_env</c> is set to <c>NULL</c>, the <c>msg</c> term is copied and the original term and its environment is still valid after the call.</p> |