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authorSverker Eriksson <[email protected]>2017-02-09 17:30:30 +0100
committerSverker Eriksson <[email protected]>2017-02-09 17:30:30 +0100
commita8d5234c77634df9522727ff200cef4fcab49c22 (patch)
tree51c3d51eaab4510928d0439265eb0613bac3a68d /erts/doc/src
parentd85e74e0c0e4bc66c875e2fd5f54d89255df0047 (diff)
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erts: Change return value for enif_select
to negative int as error and positive as success.
Diffstat (limited to 'erts/doc/src')
-rw-r--r--erts/doc/src/erl_nif.xml28
1 files changed, 14 insertions, 14 deletions
diff --git a/erts/doc/src/erl_nif.xml b/erts/doc/src/erl_nif.xml
index 9800a530f2..e8e7bd4a80 100644
--- a/erts/doc/src/erl_nif.xml
+++ b/erts/doc/src/erl_nif.xml
@@ -2583,7 +2583,7 @@ enif_map_iterator_destroy(env, &amp;iter);</code>
</func>
<func>
- <name><ret>enum ErlNifSelectReturn</ret>
+ <name><ret>int</ret>
<nametext>enif_select(ErlNifEnv* env, ErlNifEvent event, enum ErlNifSelectFlags mode,
void* obj, const ErlNifPid* pid, ERL_NIF_TERM ref)</nametext>
</name>
@@ -2626,36 +2626,36 @@ enif_map_iterator_destroy(env, &amp;iter);</code>
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>
- <p>Returns an integer where different bits indicate the outcome of the call:</p>
+ <p>Returns a non-negative value on success where the following bits can be set:</p>
<taglist>
- <tag><c>ERL_NIF_SELECT_ERROR</c></tag>
- <item>The master error bit. It will always be set if the call failed for
- any reason.</item>
<tag><c>ERL_NIF_SELECT_STOP_CALLED</c></tag>
<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>
+ </taglist>
+ <p>Returns a negative value if the call failed where the follwing bits can be set:</p>
+ <taglist>
<tag><c>ERL_NIF_SELECT_INVALID_EVENT</c></tag>
<item>Argument <c>event</c> is not a valid OS event object.</item>
<tag><c>ERL_NIF_SELECT_FAILED</c></tag>
<item>The system call failed to add the event object to the poll set.</item>
</taglist>
- <p>The return value from a successful call with <c>mode</c> as <c>ERL_NIF_SELECT_STOP</c>,
- will contain either bit <c>ERL_NIF_SELECT_STOP_CALLED</c> or
- <c>ERL_NIF_SELECT_STOP_SCHEDULED</c>.</p>
<note>
- <p>Always use bitwise AND to test the return value. New significant bits
- may be added in future releases to give more detailed information for both
- failed and successful calls. Do NOT use equallity tests like <c>==</c>, as
- that may cause your application to stop working.</p>
+ <p>Use bitwise AND to test for specific bits in the return vaue.
+ New significant bits may be added in future releases to give more detailed
+ information for both failed and successful calls. Do NOT use equallity tests
+ like <c>==</c>, as that may cause your application to stop working.</p>
<p>Example:</p>
<code type="none">
-retval = enif_select(env, fd, ERL_NIF_SELECT_READ, resource, ref);
-if (retval &amp; ERL_NIF_SELECT_ERROR) {
+retval = enif_select(env, fd, ERL_NIF_SELECT_STOP, resource, ref);
+if (retval < 0) {
/* handle error */
}
/* Success! */
+if (retval &amp; ERL_NIF_SELECT_STOP_CALLED) {
+ /* ... */
+}
</code>
</note>
</desc>