diff options
Diffstat (limited to 'erts/doc/src/erl_nif.xml')
| -rw-r--r-- | erts/doc/src/erl_nif.xml | 25 |
1 files changed, 17 insertions, 8 deletions
diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml index 95b7188882..d58ebd3171 100644 --- a/erts/doc/src/erl_nif.xml +++ b/erts/doc/src/erl_nif.xml @@ -3091,16 +3091,18 @@ 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. The return value will - tell if the event was actualy cancelled or if a notification may - already have been sent.</p> + 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 @@ -3109,7 +3111,9 @@ enif_map_iterator_destroy(env, &iter);</code> 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.</p> + 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 @@ -3192,7 +3196,11 @@ if (retval & ERL_NIF_SELECT_STOP_CALLED) { <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>.</p> + 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 @@ -3246,8 +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> |