FreeTDS Development Group

["James K. Lowden" <jklowden AT freetds.org>]

On Mon, 24 Jan 2011 13:09:45 -0300
Luis Lavena <luislavena AT gmail.com> wrote:

> Thank you for your complete and thoughtful response, but seems there
> is a confusion.
> 
> Perhaps my english is not accurate, but what I pointed out is that
> during FreeTDS cross compilation I received the compilation error, not
> anything else.

There seems to be a rule on the Internet that anyone concerned that their 
English is unclear in fact writes perfectly clearly.  :-)

We're both a little confused.  I didn't realize bsqldb.c included sqlfront.h 
(it shouldn't).  

But, when I build bsqdb, I don't see the symbol redefinition problem on 
Linux, Win32, or Win64.  (The latter two built using Microsoft's compiler du 
jour.)  

> That means FreeTDS headers are not evaluating for missing or defined
> symbols prior to define their own.

Correct: LPCBYTE is defined unconditionally as a typedef.  Microsoft's 
sqlfront.h does the same thing.  I'm saying that's OK; if you have a 
symbol-redefinition error, it's better not to include the *other* definition. 
 This code would *not* be correct in sqlfront.h:

        #ifndef LPCBYTE
        #define LPCBYTE /* ... */
        #endif

because such code *assumes* the prior definition is equivalent to the one it 
would define itself.  That's not a safe assumption: LPCBYTE has no commonly 
recognized meaning; there's no guarantee that the prior definition conforms 
to FreeTDS's requirements.  

My advice, then:

1.  Substitute sybfront.h for sqlfront.h in src/apps/bsqldb.c.  I think that 
will fix the problem.  

2.  If not, look for a way to exclude unneeded defintions when including 
windows.h.  When using Microsoft's version, I define WINDOWS_LEAN_AND_MEAN 
before including windows.h.  What you'd need for mingw I don't know.  

HTH.  

--jkl