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authorSverker Eriksson <[email protected]>2017-02-06 17:15:52 +0100
committerSverker Eriksson <[email protected]>2017-02-09 15:51:26 +0100
commit75fdce43ef567668bb89508b9b8ce0df7efaa569 (patch)
tree4b71d35042235a8a847683fe877890e22c7e874f /erts/doc/src
parent7111434c0eb1fdd6576a99ca94cdc2b20be9b9af (diff)
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erts: Add enif_monitor_process and enif_demonitor_process
Diffstat (limited to 'erts/doc/src')
-rw-r--r--erts/doc/src/erl_nif.xml67
1 files changed, 65 insertions, 2 deletions
diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml
index 8cdfc80879..bd72bdb691 100644
--- a/erts/doc/src/erl_nif.xml
+++ b/erts/doc/src/erl_nif.xml
@@ -711,6 +711,21 @@ typedef struct {
<code type="none">
typedef void ErlNifResourceDtor(ErlNifEnv* env, void* obj);</code>
<p>The function prototype of a resource destructor function.</p>
+ <p>The <c>obj</c> argument is a pointer to the resource. The only
+ allowed use for the resource in the destructor is to access its
+ user data one final time. The destructor is guaranteed to be the
+ last callback before the resource is deallocated.</p>
+ </item>
+ <tag><marker id="ErlNifResourceDown"/><c>ErlNifResourceDown</c></tag>
+ <item>
+ <code type="none">
+typedef void ErlNifResourceDown(ErlNifEnv* env, void* obj, const ErlNifPid* pid, const ErlNifMonitor* mon);</code>
+ <p>The function prototype of a resource down function,
+ called on the behalf of <seealso marker="#enif_monitor_process">
+ enif_monitor_process</seealso>. <c>obj</c> is the resource, <c>pid</c>
+ is the identity of the monitored process that is exiting, and <c>mon</c>
+ is the identity of the monitor.
+ </p>
</item>
<tag><marker id="ErlNifResourceStop"/><c>ErlNifResourceStop</c></tag>
<item>
@@ -1022,6 +1037,29 @@ typedef enum {
</func>
<func>
+ <name><ret>int</ret><nametext>enif_demonitor_process(ErlNifEnv* env, void* obj,
+ const ErlNifMonitor* mon)</nametext></name>
+ <fsummary>Cancel a process monitor.</fsummary>
+ <desc>
+ <marker id="enif_demonitor_process"></marker>
+ <p>Cancels a monitor created earlier with <seealso marker="enif_monitor_process">
+ <c>enif_monitor_process</c></seealso>. Argument <c>obj</c> is a pointer
+ to the resource holding the monitor and <c>*mon</c> identifies the monitor.</p>
+ <p>Returns <c>0</c> if the monitor was successfully identified and removed.
+ Returns a non-zero value if the monitor could not be identified, which means
+ it was either</p>
+ <list type="bulleted">
+ <item>never created for this resource</item>
+ <item>already triggered</item>
+ <item>just about to be triggered by a concurrent thread</item>
+ </list>
+ <p>This function is only thread-safe when the emulator with SMP support
+ is used. It can only be used in a non-SMP emulator from a NIF-calling
+ thread.</p>
+ </desc>
+ </func>
+
+ <func>
<name><ret>int</ret>
<nametext>enif_equal_tids(ErlNifTid tid1, ErlNifTid tid2)</nametext>
</name>
@@ -2137,6 +2175,31 @@ enif_map_iterator_destroy(env, &amp;iter);</code>
</func>
<func>
+ <name><ret>int</ret><nametext>enif_monitor_process(ErlNifEnv* env, void* obj,
+ const ErlNifPid* target_pid, ErlNifMonitor* mon)</nametext></name>
+ <fsummary>Monitor a process from a resource.</fsummary>
+ <desc>
+ <marker id="enif_monitor_process"></marker>
+ <p>Starts monitoring a process from a resource. When a process is
+ monitored, a process exit results in a call to the provided
+ <seealso marker="ErlNifResourceDown">
+ <c>down</c></seealso> callback associated with the resource type.</p>
+ <p>Argument <c>obj</c> is pointer to the resource to hold the monitor and
+ <c>*target_pid</c> identifies the local process to be monitored.</p>
+ <p>If <c>mon</c> is not <c>NULL</c>, a successful call stores the
+ identity of the monitor in the struct pointed to by <c>mon</c>.
+ This identifier is used to refer to the monitor for later removal or
+ compare. A monitor is automatically removed when it triggers or when
+ the resource is deallocated.</p>
+ <p>Returns <c>0</c> on success, &lt; 0 if no <c>down</c> callback is
+ provided, and &gt; 0 if the process is no longer alive.</p>
+ <p>This function is only thread-safe when the emulator with SMP support
+ is used. It can only be used in a non-SMP emulator from a NIF-calling
+ thread.</p>
+ </desc>
+ </func>
+
+ <func>
<name><ret>ErlNifTime</ret>
<nametext>enif_monotonic_time(ErlNifTimeUnit time_unit)</nametext>
</name>
@@ -2268,8 +2331,8 @@ enif_map_iterator_destroy(env, &amp;iter);</code>
used together with <seealso marker="#enif_select"><c>enif_select</c></seealso>.</p>
<p>Argument <c>init</c> is a pointer to an
<seealso marker="#ErlNifResourceTypeInit"><c>ErlNifResourceTypeInit</c></seealso>
- structure that contains the function pointers for the destructor and the stop callback
- of the resource type.</p>
+ structure that contains the function pointers for destructor, down and stop callbacks
+ for the resource type.</p>
</desc>
</func>