hidapi: fix "conversion from 'size_t' to 'int', possible loss of data"

[madebr]

This warning shows up when building with libusb support using MSVC.
Upstreaming of libsdl-org/SDL@1664ac4

libsdl-org/SDL#10199

[madebr]

FYI, it looks like your cmake script does not allow for easy building of hidapi with libusb.

For this, SDL uses a FindLibUSB.cmake module and a GitHub prebuilt release to provide binaries

[Youw]

FYI, it looks like your cmake script does not allow for easy building of hidapi with libusb.

Define what do you expect to be easy.
I'm using libusb-cmake and because of this (need add_subdirectory(libusb) before add_subdirectory(hidapi) ) - it is quite trivial.

[Youw]

One more thing - do you thing we could update HIDAPI CI script to catch this/similar issues in the future?

[madebr]

Define what do you expect to be easy.

By easy, I mean the cmake script does need no modifications and can build with libusb support (using a system library) without needing to building libusb yourself.

hidapi/CMakeLists.txt

Lines 40 to 48 in 4578ea2

	elseif(NOT WIN32)
	if(CMAKE_SYSTEM_NAME MATCHES "Linux")
	option(HIDAPI_WITH_HIDRAW "Build HIDRAW-based implementation of HIDAPI" ON)
	option(HIDAPI_WITH_LIBUSB "Build LIBUSB-based implementation of HIDAPI" ON)
	endif()
	if(CMAKE_SYSTEM_NAME MATCHES "NetBSD")
	option(HIDAPI_WITH_NETBSD "Build NetBSD/UHID implementation of HIDAPI" ON)
	endif()
	endif()

hidapi/src/CMakeLists.txt

Lines 110 to 130 in 4578ea2

	if(WIN32)
	target_include_directories(hidapi_include INTERFACE
	"$<BUILD_INTERFACE:${PROJECT_ROOT}/windows>"
	)
	add_subdirectory("${PROJECT_ROOT}/windows" windows)
	set(EXPORT_ALIAS winapi)
	list(APPEND EXPORT_COMPONENTS winapi)
	elseif(APPLE)
	target_include_directories(hidapi_include INTERFACE
	"$<BUILD_INTERFACE:${PROJECT_ROOT}/mac>"
	)
	add_subdirectory("${PROJECT_ROOT}/mac" mac)
	set(EXPORT_ALIAS darwin)
	list(APPEND EXPORT_COMPONENTS darwin)
	if(NOT BUILD_SHARED_LIBS)
	set(HIDAPI_NEED_EXPORT_THREADS TRUE)
	endif()
	else()
	if(NOT DEFINED HIDAPI_WITH_LIBUSB)
	set(HIDAPI_WITH_LIBUSB ON)
	endif()

HIDAPI_WITH_LIBUSB is not used on Windows

I'm using libusb-cmake and because of this (need add_subdirectory(libusb) before add_subdirectory(hidapi) ) - it is quite trivial.

It works, but you're effectively using a fork and do not use upstream.
For SDL's use case, we don't want this hard dependency: users should bring their own libusb.
This is also valid for every (mingw) distribution (e.g. msys2)

One more thing - do you thing we could update HIDAPI CI script to catch this/similar issues in the future?

Looking at SDL's cmake script, we've added a SDL_WERROR cmake option to build with -Werror//WX (default off, enabled on ci).
Recent CMake versions have a cmake property for this: configure with -DCMAKE_COMPILER_WARNING_AS_ERROR=1.
We don't pass a special MSVC warning flag.

[Youw]

Lets continue the CMake conversation at: #682