Segfault on context creation about usbtmc HOT 7 CLOSED

@brandondube

1. Do you have the libusb driver installed (e.g., brew install libusb on macOS)?
2. Did you run your Go program with root privileges (e.g., sudo myprog)?

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Libusb1.0-dev is installed (and the lib is on the path), I didn’t run with sudo but lsusb-vvv doesn’t complain about permissions / cant open devices.

‘Bare’ google/gousb context succeeded but usbtmc panics.

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Have you tried running as sudo?

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@brandondube — A few more questions:

1. What test equipment are you trying to communicate with?
2. What hardware and O/S are you using?
3. What version of libusb are you using?

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I just noticed that there had been a typo in the README if you were trying to use the google/gousb driver. The correct import statement should be:

import (
	"github.com/gotmc/usbtmc"
	_ "github.com/gotmc/usbtmc/driver/google"
)

Prior to running that, make sure you install the google/gousb driver using

$ go get -v github.com/google/gousb

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The typo is probably the cause. I'm not back at work until the week after next, but to the 1,2,3 above:

1. test equipment - Thorlabs ITC4001

2. hardware / OS -- a supermicro server (or at least one in a supermicro case, not sure who the mfg is) in a standard ATX chassis, USB 2.0 connection over the Thorlabs provided cable. Ubuntu 16.04 LTS.

3. libusb-dev 1.0.12

I did not try sudo, my user account on the server has permissions to access USB devices, but I don't have (and definitely can't get) sudo -- our IT manages that.

If it is the typo, checking if the driver is nil before the first call that uses it and bailing then would be a sensible fix. Perhaps the valid/usable import statements (_ "...") could be included in a fmt.Errorf.

In the interim, I have already made a very bare-bones impl of usbtmc for that thorlabs controller on top of google/gousb with hardcoded vid/pid, endpoint nos, etc, and bulk transfer r/w only, though it is owned by my employer so I cannot share.

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Closing due to inactivity. Let me know if this is still an issue, and I'll reopen.

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