QPSL driver is not loaded Win10 MSVC 2015 x64

koronabora

I builded psql plugin using msvc compiler with postgres 9.5.2. Nothing changed.

Please, could anybody say how to debug this situation: why plugin is not loading? There are no logs about this.

Thank you!

SGaist

Hi and welcome to devnet,

Do you also have the folder where the PostgreSQL dlls are in your PATH environment variable ? If not, then simply got to the run part of the Project panel and add it there.

koronabora

@SGaist
Yes, global %PATH% includes paths to PostgreSQL's dlls:
https://yadi.sk/i/DP7N4Xx8qvCSB

And these dll is in a root near a project binaries:

ssleay32.dll, iconv.dll, libeay32.dll, libiconv-2.dll, libintl-8.dll, libpq.dll, libxml2.dll, libxslt.dll, zlib1.dll

P.S.

I'm modified psql driver code by appending some output to console, but nothing appears at console after driver loading:

QSqlDriver* QPSQLDriverPlugin::create(const QString &name)
{
    if (name == QLatin1String("QPSQL") || name == QLatin1String("QPSQL7")) {
        QPSQLDriver* driver = new QPSQLDriver();
        std::cout << "Driver loaded by main";
        return driver;
    }
    std::cout << "Driver not loaded by main";
    return 0;
}

SGaist

After re-reading your plugin loading output, there something strange, did you copy the plugin in your application after building it ?

It should rather go in Qt's plugins SQL sub folder

koronabora

I'm sorry.

Using command line to start application:

@echo off
MoneyManagement.exe > out.txt

I see this in file "out.txt":

Driver loaded by main

In lastSqlError variable the same:

Driver not loaded Driver not loaded

And there are no error messages in MSVC output.

What I have to do?

P.S.

After appending debug output to all methods inside "qsql_psql_p.h" I saw this:

Plugin consructor called.
private sql driver constructor called
QPSQLDriver constructor 1
Driver loaded by mainQPSQLDriver close
QPSQLDriver isOpen
QPSQLDriver destructor

SGaist

After re-reading your code sample I just realized: you're using QSqlDatabase wrongly. You are currently trying to open an invalid database object.

addDatabase is a static function. See the detailed description of QSqlDatabase to see how it's done

koronabora

@SGaist

Thank you again!

_sqlBase = new QSqlDatabase();
	*_sqlBase = QSqlDatabase::addDatabase(_SQL_DRIVER); //"QPSQL"

Now all is ok.

SGaist

That's wrong, don't allocate _sqlBase on the heap.

koronabora

@SGaist

Could you explain to me, why?
Thank you.

SGaist

One of the reason is explained in QSqlDatbase::removeDatabase.