Qt + Firebird 2.5 - something wrong with the plugin?

Question

Qt

I downloaded the archive from Firebird 2.5 (not embedded). I built the plugin according to the instructions , everything seems to be ok, the necessary .dlls ( andqsqlibase ) qsqlibase4appeared.
Then I downloaded the Embedded (also, of course, 2.5) archive, got it from there fembedded.dll(renaming it, following the instructions, to fbclient.dll). Ok, I'm trying to work with all this, in the project folder there is a sqldrivers folder, in which all this stuff lies and is loaded in this way:

QPluginLoader loader;
loader.setFileName("..\\folder1\\folder2\\sqldrivers");
  
qDebug() << loader.load(); 
QMessageBox::information(0,"",QString::number(loader.load()));
qDebug() << loader.errorString();

I'm trying to start working with the base

source_database = QSqlDatabase::addDatabase("QIBASE");
source_database.setDatabaseName("./test.fdb");
source_database.setUserName("SYSDBA");
source_database.setPassword("masterkey");

However, I stumble upon an error "Driver not loaded!"
Ok, I check the available drivers

QStringList sdrivers = QSqlDatabase::drivers();
  //output all avalible drivers
for(int i = 0; i< sdrivers.size();i++)
    qDebug()<<sdrivers[i];

However, it concludes that it is available!

"QIBASE" "QSQLITE" "QODBC3" "QODBC" "QPSQL7" "QPSQL"

I put .dlls in the folder with the project executable - the same picture, I went with DependencyWalker - everything seems to be fine. What the heck? Has anyone encountered such problems?

Answer 1

As a rule, such troubles arise due to inattentive reading https://qt-project.org/doc/qt-5.0/qtdoc/deployment...