I thought that hidapi idea is to provide generic crossplatform API if possible.
We can add such option for Windows too (do not pass FILE_SHARE_READ and FILE_SHARE_WRITE to CreateFile). Maybe its better to do not-os-specific hid_open_path instead?

I thought that hidapi idea is to provide generic crossplatform API if possible. We can add such option for Windows too (do not pass `FILE_SHARE_READ` and `FILE_SHARE_WRITE` to [CreateFile](https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilew)). Maybe its better to do not-os-specific `hid_open_path` instead?

Youw commented

2022-04-13 07:44:57 -05:00

(Migrated from github.com)

I already had this conversation somewhere (but I can't find it, so here it goes again):

HID Standard doesn't define such things like sharing the device on host side, so we can't reference to any existing specification or smth;
Not all platforms supports such notion at all:
- You can do Exclusive or Non-Exclusive Open on macOS;
- (apparently) You can do Shared or Non-Shared Open on Windows (I never checked the actual behavior when you do Non-Shared Open on Windows);
- Both LIBUSB and HIDRAW backends do not support Non-Exclusive Open due to OS/API specifics;

Having a "cross-platform" function that is known only to work for some platforms defeats the whole "cross-platform" idea.

Pretty much the same thing we can tell about similar option: ReadWrite or ReadOnly Open: supported by Windows and HIDRAW, but not supported by macOS and LIBUSB. More than that - on Window you can open a device without specifying ReadWrite or ReadOnly, and on HIDRAW you have to specify one of them.

There is also a question of consistency, e.g.: "shouldn't a cross-platform application behave consistently across platforms?".
I.e. since we open on Windows in shared mode, why don't we open in Non-Exclusive mode on macOS by default?
I already asked myself this question here.
In addition to that: on LIBUSB we open with exclusive access (and there is no option to do otherwise), so current behavior on macOS is consistent with LIBUSB.

Given all of the above, my strategy is:

try&keep the existing behavior whenever possible (unless it is a bug, which better be fixed, like #334);
(recently new strategy) Add platform-specific options for options/platforms where it makes sense.

I already had this conversation somewhere (but I can't find it, so here it goes again): 1) HID Standard doesn't define such things like sharing the device on host side, so we can't reference to any existing specification or smth; 2) Not all platforms supports such notion at all: - You can do Exclusive or Non-Exclusive Open on macOS; - (apparently) You can do Shared or Non-Shared Open on Windows (I never checked the actual behavior when you do Non-Shared Open on Windows); - Both LIBUSB and HIDRAW backends do not support Non-Exclusive Open due to OS/API specifics; Having a "cross-platform" function that is known only to work for _some_ platforms defeats the whole "cross-platform" idea. Pretty much the same thing we can tell about similar option: ReadWrite or ReadOnly Open: supported by Windows and HIDRAW, but not supported by macOS and LIBUSB. More than that - on Window you can open a device without specifying ReadWrite or ReadOnly, and on HIDRAW you have to specify one of them. --- There is also a question of consistency, e.g.: "shouldn't a cross-platform application behave consistently across platforms?". I.e. since we open on Windows in shared mode, why don't we open in Non-Exclusive mode on macOS by default? I already asked myself this question [here](https://github.com/libusb/hidapi/issues/27#issuecomment-590607926). In addition to that: on LIBUSB we open with exclusive access (and there is no option to do otherwise), so current behavior on macOS is consistent with LIBUSB. --- Given all of the above, my strategy is: - try&_keep the existing behavior whenever possible_ (unless it is a bug, which better be fixed, like #334); - (recently new strategy) Add platform-specific options for options/platforms where it makes sense.

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