SQLite and UTF8 - qt

Question

I have a strange problem. Cant add function to sqlite/ Write on c++/Qt.
Function should do upper to Utf-8 simbols;
this->db = QSqlDatabase::addDatabase("QSQLITE");
this->db.setDatabaseName(db);
this->db.open();
QVariant v = this->db.driver()->handle();
sqlite3 *handler = *static_cast<sqlite3 **>(v.data());
sqlite3_create_function( handler, "myUpper", 1, SQLITE_ANY, NULL, myFunc, NULL, NULL )
and the function is:
void myFunc( sqlite3_context * ctx, int argc, sqlite3_value ** argv )
{
if( argc != 1 ) return;
QString str;
switch(sqlite3_value_type(argv[0]))
{
case SQLITE_NULL:
{
sqlite3_result_text( ctx, "NULL", 4, SQLITE_STATIC );
break;
}
case SQLITE_TEXT:
{
QString wstr((char*)sqlite3_value_text16(argv[0]));
wstr = wstr.toUpper();
sqlite3_result_text16( ctx, wstr.toStdString().c_str(), wstr.size() , SQLITE_TRANSIENT );
break;
}
default:
sqlite3_result_text( ctx, "NULL", 4, SQLITE_STATIC );
break;
}
}

Answer 1

You didn't specify the problem, but I suppose you should pass a pointer to the function:
sqlite3_create_function(handler, "myUpper", 1, SQLITE_ANY, NULL, &myFunc, NULL, NULL)
EDIT:
I you're passing to the function wstr.toStdString().c_str(). This is not allowed because the pointer returned is only temporary and will go out of scope. What I would do is:
...
case SQLITE_TEXT: {
QString wstr((char*)sqlite3_value_text(argv[0]));
wstr = wstr.toUpper();
QByteArray array = wstr.toLocal8Bit();
const char* cstr = array.data();
sqlite3_result_text(ctx, cstr, wstr.size() , SQLITE_TRANSIENT);
break;
}
...
I didn't try it so check this.