hid write and read immediatelly , return fail even set timeout =2000 ?

[myxiaonia]

i self-defined a host-client protocol over usb hid, found the issue describled in title.
if i insert a delay between write and read, it works well.
Is there any other method but delay that could boost the communication?

[myxiaonia]

[Youw]

how do you identify there is an error? hid_read returns < 0?
what is the value of hid_error when the error occures?

[myxiaonia]

read timeout and hid_read returns =0

…

在 2026年3月16日，06:14，Ihor Dutchak ***@***.***> 写道： hid_read returns < 0

[Youw]

hid_read returns =0

Is not an error - that is an indication that there is no data.

fail even set timeout =2000

Do you mean you use hid_read_timeout specifying last parameter as 2000?

What version of HIDAPI?

[myxiaonia]

you remind me, i get the reason:the special zero length packet.Hidapi works well 在 2026年3月18日，01:38，Ihor Dutchak ***@***.***> 写道： hid_read returns =0 Is not an error - that is an indication that there is no data. fail even set timeout =2000 Do you mean you use hid_read_timeout specifying last parameter as 2000? What version of HIDAPI? —Reply to this email directly, view it on GitHub, or unsubscribe.You are receiving this because you authored the thread.Message ID: ***@***.***>

[Youw]

If I got you right and your issue is resolved - go ahead and close the discussion.