Linking issue with libusb-1.0

Kaluss

Hi,
I got problem with libusb-1.0:
I got following configuration in my pro file:
unix:!macx|win32: LIBS += -L$$PWD/Scale/lib/ -llibusb-1.0
INCLUDEPATH += $$PWD/Scale/inc
DEPENDPATH += $$PWD/Scale/inc

But during build I get linking issue:
error: undefined reference to `libusb_init'

error: undefined reference to `libusb_kernel_driver_active'

an so on..

I would be grateful for any hints.

jsulm

@Kaluss said in Linking issue with libusb-1.0:

-llibusb-1.0

On UNIX/Linux this has to be:

-lusb-1.0

Kaluss

@jsulm Forgot to add: It's on Windows 11

JonB

@Kaluss
Need to know whether you are using MSVC or MinGW then? If MinGW then as per Linux.

However the error message may indicate that the .lib/.a library file was indeed found, but did not resolve the specified symbols. I have no idea whether this is supposed to be needed under Windows.

Kaluss

@Kaluss In addition. It was working on Qt 5, but when I upgraded to latest version it's started to throw those errors.

Kaluss

@JonB It's Qt_6_4_3_MinGW_64_bit, libusb-1.0.a, and it's needed to handle scale on Windows. And it was working on Qt 5 ... In some sources I found information that maybe linker flag is needed here.

JonB

@Kaluss
If it's MinGW I would expect you to need to specify -lusb-1.0 not -llibusb-1.0, as @jsulm said.

If that library was working with Qt5 but now generates "unresolved symbols" at Qt6 then things may have changed internally and you might need a different version of that library, I don't know.

Kaluss

@JonB when I change to: -lusb-1.0

I got:
error: skipping incompatible ...\Scale\lib/libusb-1.0.a when searching for -lusb-1.0
error: skipping incompatible ...\Scale\lib\libusb-1.0.a when searching for -lusb-1.0
error: skipping incompatible ...\Scale\lib/libusb-1.0.a when searching for -lusb-1.0
error: cannot find -lusb-1.0
error: skipping incompatible ...\Scale\lib/libusb-1.0.a when searching for -lusb-1.0
error: collect2.exe: error: ld returned 1 exit status

jsulm

@Kaluss said in Linking issue with libusb-1.0:

...\Scale\lib/libusb-1.0.a

This is static library. Do you also have dynamic one (.so)?

JonB

@Kaluss said in Linking issue with libusb-1.0:

error: skipping incompatible ...\Scale\lib/libusb-1.0.a when searching for -lusb-1.0

In addition to @jsulm. As you can see it has now found a matching libusb-1.0.a file and is rejecting it because it is "incompatible". Which is doubtless why you get "unresolved references". Different compiler? Different 32- vs 64-bitedness? Old version requiring a newer one?

Kaluss

@JonB Exactly, downloaded libusb version for mingw 64 and now it's working.
Thank u guys for support.