CyGetDeviceInfoVidPid and CyGetDeviceInfo handle leak

[yosuke]

Hello I am using USBserialSDK(x64,windows) to control CY7C65211. But when CyGetDeviceInfoVidPid or CyGetDeviceInfo is called, this seem to have a handle leak. I use these function to poll the device is connected or not. cyusbserial.dll version is 1.0.3.81 . Regards Yosuke.

[MallikaK_22 · Accepted solution]

Hi Yosuke,

The API to close a device handle is CyClose (CY_HANDLE) as mentioned in section 4.7 in the USB Serial API Guide: https://www.cypress.com/file/123321/download 

The reason for not closing the handle is whenever you call CyGetDeviceInfo API, a linked list is created which stores the device handle information for all the devices connected. Since we are not closing the handle, CyOpen() can use the same information and hence eliminates the need to re-create the linked list. 

You can close the handle if needed. The information regarding other devices will be deleted at the time of application closure.

Regards,

Mallika

[yosuke]

Thank you for your quick reply.

Let me check my understanding is correct.

The handles are  retrieved internally when cyGetDeviceInfoVidPid is called.

So ,to prevent a handle leak,cyOpen and cyClose are should be called after cyGetDeviceInfoVidPid.

Is correct?

Below is current pseudo code.

    while (1) {

        //Array size of cyDeviceInfoList is 16 

        cyReturnStatus = CyGetDeviceInfoVidPid(cyVidPid, deviceID, (PCY_DEVICE_INFO)&cyDeviceInfoList, &cyNumDevices, 16);

    }

Should I modify it as follows to fix the issue?

    while (1) {

        //Array size of cyDeviceInfoList is 16 

        cyReturnStatus = CyGetDeviceInfoVidPid(cyVidPid, deviceID, (PCY_DEVICE_INFO)&cyDeviceInfoList, &cyNumDevices, 16);

        for (int i=0;i<cyNumDevices;,i++){

           CY_HANDLE handle;

           CyOpen(i, 0, &handle);

           CyClose(handle); 

         }

    }

Regards.

[MallikaK_22]

Hi,

Yes it seems correct. Using CyClose () shouldn't cause any issues.

Regards,

Mallika

[yosuke]

I tried the modified code, but the number of handles still increases with each CyGetDeviceInfoVidPid　function call.

Could you please investigate if there is a problem with the CyGetDeviceInfoVidPid function?

Regards.

Yosuke

[MallikaK_22]

Hi,

Apologies for the delay in response. Did you use Cy_Close()?

[yosuke]

Hi,

Yes, I used CyGetDeviceInfoVidPid() with CYOPEN() and CYCLOSE(),but still get a handle leak.

The handle I mean here is not the CY_HANDLE, but the handle displayed in the Task Manager.(see below  https://mywindowshub.com/how-to-check-task-manager-handles-for-solving-port-exhaustion-issues-on-win... )

With each call to CyGetDeviceInfoVidPid or CyGetDeviceInfo, the number of handles increases. This means that a handle leak is occurring.

Regards.

Yosuke