static globals in SSQL macro expansion -> multiple definition linker errors

[Wolfram Arnold]

Hi,

While we're talking about wish-lists for version 2.0, I have an item to
contribute.  In fact, it surprised me this hasn't been addressed yet, or
maybe I'm missing something.

The SSQL macro expansion will create static globals that are being
defined (assinged) as part of the macro.  With the ssqls-pretty tool it
was easy to see that...

sql_create_7(PriceData,
	     6,
	     7,
	     Date, date,
	     int, open,
	     int, high,
	     int, low,
	     int, close,
	     int, volume,
	     int, suspended);

...expands into...


struct PriceData {
[...]
  static const char *names[];
  static const char *_table;
[...]
};

[...]

const char *PriceData::names[] = {
"date" , "open" , "high" , "low" , "close" , "volume" , "suspended" };

[...]

This is fine and dandy, as long as the SSQL macro expansion is used in
only one .cpp source file in the application.  If the SSQL macro is put
into a header file and include it into multiple .cpp source files, then
the linker will invariably complain that names and _tables are multiply
defined symbols.

I've only tried this with version 1.7.35 so far, but I haven't seen
anything in the release notes since that this behavior has been changed.

Can this be fixed?  Not being able to share SSQL structures across
compilation units inhibits code modularity in cases where the Database
table is the common data structure shared between many different clients
in an application.

Could the macro be split into two or take an extra flag to optionally
not generate the definition for the globals?  I'd be glad to give this a
shot, but I wanted to hear from the community if there is any reason
other than lack of volunteers.  This has come up before; I found mailing
list articles as far back as 2001 on this.

Cheers,

Wolfram


-- 
Wolfram Arnold <wolfram@stripped>