[Qt-interest] dll extension to sqlite (implemented with Qt)

[Sylvain Pointeau]

hello,

I am facing a very bizarre issue.
I am on mac os x 64 bits.

I am using the sqlite3 client in a shell or shell script.

inside the sql scripts, I needed a uuid() function that generates GUID.
I created then a dll with Qt like:

#include "/usr/local/include/sqlite3ext.h"
SQLITE_EXTENSION_INIT1

#include <QtCore/QUuid>
#include <string.h>

extern "C" void sqlite3_uuid(sqlite3_context *context, int argc,
sqlite3_value **argv){
QUuid uuid = QUuid::createUuid();
QString s = uuid;
s.remove(0,1);
s.remove(s.size()-1,1);
 QByteArray to_utf8 = s.toAscii();
 sqlite3_result_text( context, to_utf8.constData(), -1, SQLITE_TRANSIENT );
}

extern "C" int sqlite3_extension_init(
   sqlite3 *db,
   char **pzErrMsg,
   const sqlite3_api_routines *pApi
){
SQLITE_EXTENSION_INIT2(pApi)
sqlite3_create_function(db, "uuid", 0, SQLITE_UTF8, 0, sqlite3_uuid, 0, 0);
return 0;
}

I compiled Qt with cocoa

Now, a little more details on how I use the extension with sqlite3:

In my shell script, I am running sqlite3 on all files of a folder:

find "./scripts" -iname "*.sql" | while read sqlfile
do
echo " -- ${sqlfile}"
/usr/local/bin/sqlite3 mydb.db3 < $sqlfile;
done

and in my sql script, I am loading the dll extension made with Qt:

.load ../../libsqliteextensions.dylib

The compilation of the dll goes like:

g++ -c -pipe -g -gdwarf-2 -arch x86_64 -Xarch_x86_64
-mmacosx-version-min=10.5 -Wall -W -fPIC -DQT_CORE_LIB -DQT_SHARED
-I/usr/local/Trolltech/Qt-4.7.0/mkspecs/macx-g++ -I.
-I/usr/local/Trolltech/Qt-4.7.0/lib/QtCore.framework/Versions/4/Headers
-I/usr/local/Trolltech/Qt-4.7.0/include/QtCore
-I/usr/local/Trolltech/Qt-4.7.0/include -Icompil/moc
-F/usr/local/Trolltech/Qt-4.7.0/lib -o compil/obj/sqliteextensions.o
src/sqliteextensions.cpp

g++ -headerpad_max_install_names -arch x86_64 -Xarch_x86_64
-mmacosx-version-min=10.5 -single_module -dynamiclib -compatibility_version 1.0
-current_version 1.0.0 -install_name libsqliteextensions.1.dylib -o
libsqliteextensions.1.0.0.dylib compil/obj/sqliteextensions.o
 -F/usr/local/Trolltech/Qt-4.7.0/lib -L/usr/local/Trolltech/Qt-4.7.0/lib
-L/usr/local/lib/ -framework QtCore -L/usr/local/Trolltech/Qt-4.7.0/lib

then after when I run a script, only in a shell, when I first try to insert
a GUID
like "insert into XXX (ID) values (uuid())"
it says that the primary key already exists, which is obviously wrong.
However, this error occurs only in a shell script, not directly from the
command line (unbelievable!).

I could only fallback to use uuid from boost and it works perfectly.

Is it safe to use Qt to implement an extension dll?
Do you have any idea on what happens here? (any hints?)

I have no idea how to narrow down the problem,
is someone interested to investigate? if yes I can build a minimal project
(and try to reproduce the same issue)

Any hints are warmly welcome.

Best regards,
Sylvain
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