Document that PQexec() can handle a NULL res pointer just fine.

Backpatch to 9.1.

Mark Hills

diff --git a/doc/src/sgml/libpq.sgml b/doc/src/sgml/libpq.sgml
index f2f67e20ffd5c5a3efe2f59733028519f45f1163..3d5f98ba2a663d5bbf2e8f9cdb1e25e6b9e3edfc 100644 (file)
--- a/doc/src/sgml/libpq.sgml
+++ b/doc/src/sgml/libpq.sgml
@@ -62,7 +62,7 @@
    return a non-null object pointer, unless perhaps there is too
    little memory even to allocate the PGconn object.
    The PQstatus function should be called to check
-   whether a connection was successfully made before queries are sent
+   the return value for a successful connection before queries are sent
    via the connection object.
 
    
@@ -1754,8 +1754,10 @@ PGresult *PQexec(PGconn *conn, const char *command);
         Returns a PGresult pointer or possibly a null
         pointer.  A non-null pointer will generally be returned except in
         out-of-memory conditions or serious errors such as inability to send
-        the command to the server.  If a null pointer is returned, it should
-        be treated like a PGRES_FATAL_ERROR result.  Use
+        the command to the server.  The PQresultStatus function
+        should be called to check the return value for any errors (including
+        the value of a null pointer, in which case it will return
+        PGRES_FATAL_ERROR).  Use
         PQerrorMessage to get more information about such
         errors.