Problem using the QPSQL plugin on Windows x64 in Debug mode

[code_talker]

I installed PostgreSQL, then downloaded and installed libpq64. Afterwards, I downloaded the Qt 4.6.2 source code and compiled it successfully with Visual Studio 2008. After providing the path to the libs in libpq64, I compiled the QPSQL sucessfully too.

My sql plugin folder contains the following files:

V:\windows\x64\QT-4.6.2_VC9.0_Bin\plugins\sqldrivers>dir *.dll 
 Datenträger in Laufwerk V: ist Data
 Verzeichnis von V:\windows\x64\QT-4.6.2_VC9.0_Bin\plugins\sqldrivers
qsqlite4.dll     
qsqlited4.dll    
qsqlpsql4.dll    
qsqlpsqld4.dll

V:\windows\x64\QT-4.6.2_VC9.0_Bin\plugins\sqldrivers>dir *.dll 
 Datenträger in Laufwerk V: ist Data
 Verzeichnis von V:\windows\x64\QT-4.6.2_VC9.0_Bin\plugins\sqldrivers
qsqlite4.dll     
qsqlited4.dll    
qsqlpsql4.dll    
qsqlpsqld4.dll

To copy to clipboard, switch view to plain text mode 

I use a simple test program:

main(int  argc , char* argv[])
{
  QApplication app(argc,argv);  // load plugins
  std::cout << "QSqlDatabase::drivers() output: " << QSqlDatabase::drivers().join(QString("; ")).toLatin1().data() << "\n"; //
output of all loaded sql plugins
 
  return 0;
}

main(int  argc , char* argv[])
{
  QApplication app(argc,argv);  // load plugins
  std::cout << "QSqlDatabase::drivers() output: " << QSqlDatabase::drivers().join(QString("; ")).toLatin1().data() << "\n"; //
output of all loaded sql plugins

  return 0;
}

To copy to clipboard, switch view to plain text mode 

The output in Release Mode:
QSqlDatabase::drivers(): QSQLITE; QPSQL7; QPSQL

The output in Debug Mode:
QSqlDatabase::drivers(): QSQLITE

As you can see, the QPSQL plugin is not loaded in debug mode.


I debugged into the qt code, the problem is in
qlibrary_win.cpp Line 70:

pHnd = LoadLibrary((wchar_t*)QDir::toNativeSeparators(attempt).utf16());

pHnd = LoadLibrary((wchar_t*)QDir::toNativeSeparators(attempt).utf16());

To copy to clipboard, switch view to plain text mode 

returns 0x00000000 for qsqlpsqld4.dll


My PATH variable contains

PATH=V:\windows\x64\QT-4.6.2_VC9.0_Bin\bin;V:\windows\x64\libpq64;"V:\toolkits\windows\x64\PostgreSQL\bin";[...]

PATH=V:\windows\x64\QT-4.6.2_VC9.0_Bin\bin;V:\windows\x64\libpq64;"V:\toolkits\windows\x64\PostgreSQL\bin";[...]

To copy to clipboard, switch view to plain text mode 

These paths contain the following DLLs:

libeay32.dll
libpq.dll
ssleay32.dll
 
comerr32.dll
gssapi32.dll
iconv.dll
k5sprt32.dll
krb5_32.dll
libeay32.dll
libiconv-2.dll
libintl-8.dll
libpq.dll
libxml2.dll
libxslt.dll
msvcr71.dll
ssleay32.dll
zlib1.dll

libeay32.dll
libpq.dll
ssleay32.dll

comerr32.dll
gssapi32.dll
iconv.dll
k5sprt32.dll
krb5_32.dll
libeay32.dll
libiconv-2.dll
libintl-8.dll
libpq.dll
libxml2.dll
libxslt.dll
msvcr71.dll
ssleay32.dll
zlib1.dll

To copy to clipboard, switch view to plain text mode 

What am I missing? How can I use the QPSQL plugin in debug mode?

Thank you for your help.