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-rw-r--r--doc/src/sgml/libpq.sgml38
1 files changed, 30 insertions, 8 deletions
diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index 25646f6f8e0..783e8e750bb 100644
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -2678,22 +2678,44 @@ const char *PQparameterStatus(const PGconn *conn, const char *paramName);
</listitem>
</varlistentry>
+ <varlistentry id="libpq-PQfullProtocolVersion">
+ <term><function>PQfullProtocolVersion</function><indexterm><primary>PQfullProtocolVersion</primary></indexterm></term>
+
+ <listitem>
+ <para>
+ Interrogates the frontend/backend protocol being used.
+<synopsis>
+int PQfullProtocolVersion(const PGconn *conn);
+</synopsis>
+ Applications might wish to use this function to determine whether certain
+ features are supported. The result is formed by multiplying the server's
+ major version number by 10000 and adding the minor version number. For
+ example, version 3.2 would be returned as 30002, and version 4.0 would
+ be returned as 40000. Zero is returned if the connection is bad. The 3.0
+ protocol is supported by <productname>PostgreSQL</productname> server
+ versions 7.4 and above.
+ </para>
+ <para>
+ The protocol version will not change after connection startup is
+ complete, but it could theoretically change during a connection reset.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="libpq-PQprotocolVersion">
<term><function>PQprotocolVersion</function><indexterm><primary>PQprotocolVersion</primary></indexterm></term>
<listitem>
<para>
- Interrogates the frontend/backend protocol being used.
+ Interrogates the frontend/backend protocol major version.
<synopsis>
int PQprotocolVersion(const PGconn *conn);
</synopsis>
- Applications might wish to use this function to determine whether certain
- features are supported. Currently, the possible values are 3
- (3.0 protocol), or zero (connection bad). The protocol version will
- not change after connection startup is complete, but it could
- theoretically change during a connection reset. The 3.0 protocol is
- supported by <productname>PostgreSQL</productname> server versions 7.4
- and above.
+ Unlike <xref linkend="libpq-PQfullProtocolVersion"/>, this returns only
+ the major protocol version in use, but it is supported by a wider range
+ of libpq releases back to version 7.4. Currently, the possible values are
+ 3 (3.0 protocol), or zero (connection bad). Prior to release version
+ 14.0, libpq could additionally return 2 (2.0 protocol).
</para>
</listitem>
</varlistentry>