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authorTom Lane2000-03-26 01:00:17 +0000
committerTom Lane2000-03-26 01:00:17 +0000
commitcb3b3eda9a2a35a9ed2ad2eb97cd0355226499de (patch)
treecc7d85856276f65f097acf9257d4c8900806520f
parentd2684ea712773104ab417ba76c3b821c6349639a (diff)
In PQnotifies discussion, reference PQsocket as function needed to get
file descriptor number for select(). (Suggestion from Ken Wright.)
-rw-r--r--doc/src/sgml/libpq.sgml14
1 files changed, 9 insertions, 5 deletions
diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index b700ce44975..c8cc2ee3e66 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -1460,13 +1460,17 @@ deprecated as a waste of processing power.
<para>
A better way to check for NOTIFY
messages when you have no useful queries to make is to call
-<function>PQconsumeInput()</function>, then check <function>PQnotifies()</function>.
+<function>PQconsumeInput()</function>, then check
+<function>PQnotifies()</function>.
You can use <function>select</function>(2) to wait for backend data to
arrive, thereby using no <acronym>CPU</acronym> power unless there is something
-to do. Note that this will work OK whether you use <function>PQsendQuery</function>/
-<function>PQgetResult</function> or simply <function>PQexec</function> for
-queries. You should, however, remember to check <function>PQnotifies()</function>
-after each <function>PQgetResult</function> or <function>PQexec</function> to see
+to do. (See <function>PQsocket()</function> to obtain the file descriptor
+number to use with <function>select</function>.)
+Note that this will work OK whether you submit queries with
+<function>PQsendQuery</function>/<function>PQgetResult</function> or simply
+use <function>PQexec</function>. You should, however, remember to
+check <function>PQnotifies()</function> after each
+<function>PQgetResult</function> or <function>PQexec</function>, to see
if any notifications came in during the processing of the query.
</para>