function is blocked ! The function is created as dll exported function use QTimer QEventLoop, when is preferenced in visual studio.

[changtj]

code as follow

//qt 
#ifdef QTFTP_DLL_EXPORT
#define DLL_API extern "C" __declspec( dllexport)
#else
#define DLL_API extern "C"  __declspec( dllimport)
#endif
#include <QTimer>
#include <QEventLoop>
DLL_API void __stdcall MyFtpTestTimer2()
{
    QTimer qt;
    QEventLoop el;
    QObject::connect( &qt, SIGNAL(timeout()), &el, SLOT(quit()));
    qt.start( 1000);
    el.exec();
}

//visual studio 2017 sdk8.1
void CMyDlg::OnTest()
{
	// TODO: 在此添加命令处理程序代码
	MyFtpTestTimer2();
}

and the cpu is taked up more.

[VRonin]

What is the problem?

[changtj]

@VRonin
the function block.

[VRonin]

yes, el.exec(); is a blocking call so the function is doing exactly what you are telling it to do

[changtj]

@VRonin

//your code here
QTimer qt;
DLL_API void __stdcall MyFtpTestTimer2()
{
    QTimer qt;
    QEventLoop el;
    QObject::connect( &qt, SIGNAL(timeout()), &el, SLOT(quit()));
    qt.start( 1000);
    el.exec();
}

the function do not return any more in vs. when it is used in qt it only block 1000 ms when qt timed out. as qt.start( 1000).

[VRonin]

I think QEventLoop needs a QCoreApplication to be created before being usable