Opening multiple handles to driver (How to do both synchronous and asynchronous io with DeviceIoControl?)


I have a driver which handles some  IOCTLS that are synchronous, and one that is asynchronous. Can I / should I do 2 CreateFile() calls, one without FILE_FLAG_OVERLAPPED for the synchronous, and one with for the asynchronous? Is there any problem with this from the point of view that there is more than one handle to the driver open simultaneously? Does it depend on the driver?

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>> Is there any problem with this from the point of view that there is more than one handle
>>to the driver open simultaneously?

No, that happens all the time. The driver itself is responsible to handle that correctly, i.e. if the driver is responsible for an exclusive resource (such as a serial port), it should not allow to create a 2nd handle, but if it does, it is supposed to be able to run smoothly.

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