Author: wyoung
Date: Sat Oct 27 09:46:54 2007
New Revision: 1811
URL: http://svn.gna.org/viewcvs/mysqlpp?rev=1811&view=rev
Log:
Added a section to the SSQLS chapter in the userman describing
MYSQLPP_SSQLS_NO_STATICS: why and how to use it.
Modified:
trunk/Wishlist
trunk/doc/userman/userman.dbx
Modified: trunk/Wishlist
URL:
http://svn.gna.org/viewcvs/mysqlpp/trunk/Wishlist?rev=1811&r1=1810&r2=1811&view=diff
==============================================================================
--- trunk/Wishlist (original)
+++ trunk/Wishlist Sat Oct 27 09:46:54 2007
@@ -12,10 +12,6 @@
The items in this section are those things we definitely want to
get done in v3.0. Most of them break the ABI, so they can't wait
for a future version, because v4 could be years out.
-
- o Update userman references to util module
-
- o Document MYSQLPP_SSQLS_NO_STATICS
o Audit use of headers in lib/*.h, to reduce dependencies.
Modified: trunk/doc/userman/userman.dbx
URL:
http://svn.gna.org/viewcvs/mysqlpp/trunk/doc/userman/userman.dbx?rev=1811&r1=1810&r2=1811&view=diff
==============================================================================
--- trunk/doc/userman/userman.dbx (original)
+++ trunk/doc/userman/userman.dbx Sat Oct 27 09:46:54 2007
@@ -1647,6 +1647,42 @@
<sect2>
+ <title>Using an SSQLS in Multiple Modules</title>
+
+ <para>Unless you use one of the emasculated forms of SSQLS
+ described below, you'll run into a problem when trying to
+ use it in more than one module. The more advanced forms of
+ SSQLS include a few static data members to hold information
+ common to all structures of that type. (The table name and
+ the list of field names.) A typical way to run into this
+ is to put the SSQLS definition in a header file and then
+ <userinput>#include</userinput> that in all the modules that
+ need to use SSQLSes of that type. This results in each module
+ defining its own copy of the static data members, which causes
+ a multiply-defined symbol error at link time.</para>
+
+ <para>The way around this is to add this before all but one
+ of the places where you pull in the header definining the
+ SSQLS:</para>
+
+ <programlisting>
+#define MYSQLPP_SSQLS_NO_STATICS</programlisting>
+
+ <para>This suppresses the static data members in any SSQLS
+ defined thereafter.</para>
+
+ <para>These data members must exist, so one (and only
+ one!) module must bring in the SSQLS definition without
+ this being defined. Thus, you don't want to put this
+ <userinput>#define</userinput> in the header file with the
+ SSQLS definition. It's usually easy to find one module in a
+ program that logically "owns" each SSQLS, and it can pull in
+ the header definining the SSQLS directly, without suppressing
+ the static data members.</para>
+ </sect2>
+
+
+ <sect2>
<title>Harnessing SSQLS Internals</title>
<para>Continuing the discussion in the previous section,
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