QPSQL driver cannot be loaded

KK2022

Hello,
I am combing through the forums and information on the internet to find a solution.
I am trying to run the following code on my Windows 11 PC with Qt 5.15 Mingw 32 Bit compiler.

    m_db = QSqlDatabase::addDatabase("QPSQL");
    m_db.setHostName("192.168.112.70");
    m_db.setDatabaseName("myDB");
    m_db.setUserName("user");
    m_db.setPassword("pwd");

    qDebug() << "Available Drivers: " << QSqlDatabase::drivers();

    if (!m_db.open()) {
        qDebug() << "Failed to connect to database:" << m_db.lastError().text();
    }

I get the following debug information with QT_DEBUG_PLUGINS=1

QFactoryLoader::QFactoryLoader() looking at "C:/Qt/5.15.2/mingw81_32/plugins/sqldrivers/qsqlpsql.dll"
Found metadata in lib C:/Qt/5.15.2/mingw81_32/plugins/sqldrivers/qsqlpsql.dll, metadata=
{
    "IID": "org.qt-project.Qt.QSqlDriverFactoryInterface",
    "MetaData": {
        "Keys": [
            "QPSQL7",
            "QPSQL"
        ]
    },
    "archreq": 0,
    "className": "QPSQLDriverPlugin",
    "debug": false,
    "version": 331520
}

Got keys from plugin meta data ("QPSQL7", "QPSQL")
QFactoryLoader::QFactoryLoader() checking directory path "C:/Users/user/Documents/Qt_Projects/display-software/build/Desktop_Qt_5_15_2_MinGW_32_bit-Debug/debug/sqldrivers" ...
Cannot load library C:\Qt\5.15.2\mingw81_32\plugins\sqldrivers\qsqlpsql.dll: Unknown error 0x000000c1.
QLibraryPrivate::loadPlugin failed on "C:/Qt/5.15.2/mingw81_32/plugins/sqldrivers/qsqlpsql.dll" : "Cannot load library C:\\Qt\\5.15.2\\mingw81_32\\plugins\\sqldrivers\\qsqlpsql.dll: Unknown error 0x000000c1."
QSqlDatabase: QPSQL driver not loaded
QSqlDatabase: available drivers: QSQLITE QODBC QODBC3 QPSQL QPSQL7
Available Drivers:  ("QSQLITE", "QODBC", "QODBC3", "QPSQL", "QPSQL7")
Failed to connect to database: "Driver not loaded Driver not loaded"

I checked the username password and the connection using pg admin 4 software with the hostname given above and it responds and works as expected.

The .dll file is in the path C:\Qt\5.15.2\mingw81_32\plugins\sqldrivers\ as shown in the debug info above and I ran Dependencies on the dll file and I think everything is ok.

I uninstalled PostgreSQL 16 and installed PostgreSQL 9.6 32-bit version and added the bin folder to the System Path, although the actual database is on a linux 64-bit server on the network running PostgreSQL 13.
What could be the problem that I am not seeing and how do I load the QPSQL library?

Thank you so much in advance.

Christian Ehrlicher

See e.g. https://forum.qt.io/topic/136580/ - are you sure that you built for 32bit?

KK2022

@Christian-Ehrlicher Thank you for responding.
Yes I am. I have only one kit configured for this projecct at the moment which is using MinGW 8.1 with QtCreator 14.0.1 (if it matters).