libusb.h: No such file or directory

[huojiujian1]

When attempting to compile Qt open source, I encountered the error 'libusb.h: No such file or directory.' Despite following methods found online to add the library, I still cannot successfully compile it.

[jankae]

Without knowing what exactly you did, I can not help you here. The message simply tells me that your compiler can not find the libusb header. Make sure to either copy this file into the include path of your compiler or add the location of the file to the search path for includes.

[jankae]

no need to apologize and I would have preferred helping you more but without knowing what exactly you installed (compiler, Qt version, libusb location,...) this is very difficult. Unfortunately, integrating external libraries in C/C++ is not as easy as e.g. in Python

[huojiujian1]

My compiler and QT version are Desktop Qt 6.5.3 MinGW 64-bit. The location of the libusb library is on the desktop. Also, I saw the code for adding the libusb library in the.pro file. After adding the path where my libusb library is located, namely C:$\Users\1123g\Desktop\libusb-1.0.27\MinGW64, I found that compilation failed.

[jankae]

Can you post a screenshot of the error message and your modified .pro file as well? Not sure how familiar you are with C++ toolchains but there are two distinct steps: compiling and linking. Your "libusb.h: no such file or directory" is a compiler error. To fix it, you need to point your compiler to the directory of the libusb.h file.
What you are doing with the path to the library is only influencing the linker. You likely will have to do this anyway (otherwise you will get a linker error next) but at this point it will have no influence whatsoever on your compiler error.

With you setup, I would put the libusb.h here in a first attempt:
C:/Qt/6.5.3/mingw_64/include/libusb-1.0/libusb.h
This is a bit ugly (it requires you to repeat this when you update to new Qt versions) but probably the easiest way to solve your compiler error.

[huojiujian1]

[jankae]

Well, you have the include path shown right there. Looks a bit weird with the Qt6.7 followed by Qt6.5.3 but if that is your include path maybe try putting the libusb.h there?
The compiler is looking for "libusb-1.0/libusb.h" relative to your include path, so the file should be placed like this:
D:/Qt6.7/Qt6.5.3/mingw_64/include/libusb-1.0/libusb.h