DBT_DEVICEARRIVAL events, access to a number of equipment at the same time-CodePudding

DBT_DEVICEARRIVAL events, access to a number of equipment at the same time, can only capture two, who had tried? Is 3 ~ 4 U disk inserted at the same time, can only capture two DBT_DEVICEARRIVAL events

CodePudding user response:

Didn't try, dare not speak

CodePudding user response:

reference 1st floor gz_qmc response:

didn't try, dare not speak

This news closed, if it is below 2, there is no problem, access to three at the same time, always lose 1, access to 4 at the same time, always lost two

CodePudding user response:

Get the number of more than 2

But at the same time insert is what mean? A few people together to put this test?

CodePudding user response:

reference boylafong reply: 3/f

can obtain the number of more than 2

But at the same time insert is what mean? A few people together to put this test?

For, according to the sequential access, as long as there is time difference, can receive, but at the same time access, is almost a loss under the condition of time,
I am looking for a usb hub to do experiments, filled it with U disk, and then put the hub connected to the usb port

CodePudding user response:

Haven't tried all of a sudden quick pulling/insert so many USB devices,,
Guess:
The system broadcasts The DBT_DEVICEARRIVAL device event when a device or piece of media has had been inserted and becomes available.
It is also the thing reaction cycle?

It is recommended to use DBT_DEVNODES_CHANGED to test,

CodePudding user response:

reference 5 floor easunlee reply:

haven't tried all of a sudden quick pulling/insert so many USB devices,,
Guess:
The system broadcasts The DBT_DEVICEARRIVAL device event when a device or piece of media has had been inserted and becomes available.
It is also the thing reaction cycle?

Recommended DBT_DEVNODES_CHANGED to detect,

I am win10 development environment, then run under Windows 7, than win10 effect is better

CodePudding user response:

reference 5 floor easunlee reply:

haven't tried all of a sudden quick pulling/insert so many USB devices,,
Guess:
The system broadcasts The DBT_DEVICEARRIVAL device event when a device or piece of media has had been inserted and becomes available.
It is also the thing reaction cycle?

Recommended DBT_DEVNODES_CHANGED to detect,

And this DBT_DEVNODES_CHANGED, can't get U disk drive

CodePudding user response:

No one knows, no one tried it, to be exact, DBT_DEVTYP_VOLUME not receive

CodePudding user response:

Personal advice, sweep after the message is received, the GetDriveType ==DRIVE_REMOVABLE (szDrv)

CodePudding user response:

references 9 f zgl7903 response:

personal advice, sweep after the message is received, the GetDriveType (szDrv)==DRIVE_REMOVABLE

I got any news? DBT_DEVICEARRIVAL this?

CodePudding user response:

references to the tenth floor jackyleu response:

Quote: references 9 f zgl7903 response:

Personal advice, sweep after the message is received, the GetDriveType (szDrv)==DRIVE_REMOVABLE

I got any news? DBT_DEVICEARRIVAL this

WM_DEVICECHANGE

CodePudding user response:

11 references zgl7903 response:

Quote: reference to the tenth floor jackyleu response:

Quote: references 9 floor zgl7903 response:

Personal advice, sweep after the message is received, the GetDriveType (szDrv)==DRIVE_REMOVABLE

I got any news? DBT_DEVICEARRIVAL this

WM_DEVICECHANGE

Can say some detailed? What's the purpose, I want to drive, can only be DBT_DEVTYP_VOLUME this?

CodePudding user response:

11 references zgl7903 response:

Quote: reference to the tenth floor jackyleu response:

Quote: references 9 floor zgl7903 response:

Personal advice, sweep after the message is received, the GetDriveType (szDrv)==DRIVE_REMOVABLE

I got any news? DBT_DEVICEARRIVAL this

WM_DEVICECHANGE

This also tried, or access 3 USB storage devices at the same time, can only handle one, four, can handle only two

CodePudding user response:

Type dbcv_unitmask out look, and in the calculator in binary view how a few bit is set to 1, added several volumes,

 case WM_DEVICECHANGE: 
The switch (wParam) 
{
Case DBT_DEVICEARRIVAL: 
If (((PDEV_BROADCAST_HDR) lParam) - & gt; Dbch_devicetype==DBT_DEVTYP_VOLUME) 
{
PDEV_BROADCAST_VOLUME pdvol=(lParam PDEV_BROADCAST_VOLUME); 
Printf (" % 0 x 8 x \ n ", pdvol - & gt; Dbcv_unitmask); 
} 
break; 

Case DBT_DEVICEREMOVECOMPLETE: 
If (((PDEV_BROADCAST_HDR) lParam) - & gt; Dbch_devicetype==DBT_DEVTYP_VOLUME) 
{
PDEV_BROADCAST_VOLUME pdvol=(lParam PDEV_BROADCAST_VOLUME); 
Printf (" % 0 x 8 x \ n ", pdvol - & gt; Dbcv_unitmask); 
} 
break; 

Default: 
break; 
} 
break;

CodePudding user response:

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