<div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr"><div dir="ltr">Okay, it seems I've gotten the "hello world" almost working<div><br></div><div>The only problem left is that trying to read the "user_data" pointer returned gives garbage.</div><div>When I submit the event, I attach a struct to it, like this:</div><div><br></div><div><div> MemorySegment myStruct = MemorySegment.allocateNative(myStructLayout, session);</div><div> myStruct$foo.set(myStruct, 1);</div><div> myStruct$bar.set(myStruct, 2);</div><div> io_uring_sqe_set_data(sqePtr, myStruct);</div></div><div><br></div><div>Then when the results come back, I am doing this to read the userdata pointer:</div><div><br></div><div><div> MemorySegment cqes = io_uring_cqe.allocateArray(1, allocator);</div><div> io_uring_wait_cqe(ring, cqes);</div><div> // cqes[0]</div><div> MemorySegment cqe = cqes.asSlice(0, io_uring_cqe.$LAYOUT().byteSize());</div><div> // cqes[0]->user_data</div><div> MemoryAddress user_data = MemoryAddress.ofLong(io_uring_cqe.user_data$get(cqe));</div><div> MemorySegment user_data_segment = MemorySegment.ofAddress(user_data, myStructLayout.byteSize(), session);</div></div><div><br></div><div>I try to print it out, comparing the "foo" and "bar" field against the original values of "1" and "2"</div><div><br></div><div><div> user_data->foo=1480561120</div><div> user_data->bar=32545</div></div><div><br></div><div>Does anyone know/see what I am doing wrong here? 🤔</div><div><div><a href="https://gist.github.com/GavinRay97/8ea0997693c00f8df61968a98ba30135#file-io_uring-java-L48-L55">https://gist.github.com/GavinRay97/8ea0997693c00f8df61968a98ba30135#file-io_uring-java-L48-L55</a></div></div></div></div></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Sep 21, 2022 at 8:18 PM Gavin Ray <<a href="mailto:ray.gavin97@gmail.com">ray.gavin97@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div dir="ltr">@Daniel, I didn't know the lwjgl folks were looking into this area, I've had a brief look but it's definitely something I want to check out more!<div><br></div><div>@Maurizio, the idea about defining a second library that depends on it is pretty clever.</div><div><br></div><div>It turns out that you can pull liburing in with CMake without so much effort</div><div>To set that scenario up was just the below code, this should work decently 👍</div><div><br></div><div>=============================</div><div><div>ExternalProject_Add(</div><div> liburing_git</div><div> GIT_REPOSITORY <a href="http://github.com/axboe/liburing.git" target="_blank">http://github.com/axboe/liburing.git</a></div><div> GIT_TAG liburing-2.2</div><div> BUILD_IN_SOURCE 1</div><div> BUILD_BYPRODUCTS "<SOURCE_DIR>/src/liburing.a"</div><div> BUILD_COMMAND make</div><div>)</div><div>ExternalProject_Get_Property(liburing_git SOURCE_DIR)</div><div>add_library(liburing INTERFACE)</div><div>add_dependencies(liburing liburing_git)</div><div>target_include_directories(liburing INTERFACE ${SOURCE_DIR}/src/include)</div><div>target_link_libraries(liburing INTERFACE ${SOURCE_DIR}/src/liburing.a)</div><div><br></div><div># NOW LINK IT TO SECOND LIBRARY</div><div>add_library(liburing_extras SHARED liburing_extras/main.c)</div><div>target_link_libraries(liburing_extras liburing)</div><div>add_dependencies(liburing_extras liburing)</div></div><div><br></div></div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Wed, Sep 21, 2022 at 7:24 PM Maurizio Cimadamore <<a href="mailto:maurizio.cimadamore@oracle.com" target="_blank">maurizio.cimadamore@oracle.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><br>
On 21/09/2022 23:39, Gavin Ray wrote:<br>
> That makes sense -- I will look at patching liburing with a dirty <br>
> one-liner that strips "static inline" from the definitions that have <br>
> them then, ty =)<br>
<br>
Sorry, hit send too fast, and forgot to reply to this.<br>
<br>
There are few approaches that can be tried.<br>
<br>
First, you could define another shared library that depends on io_uring <br>
- e.g. a C file which includes the io_uring header. This new file would <br>
contain _new_ exported symbols for all the static inline functions, <br>
whose implementation just delegates to the underlying static inline <br>
functions (in the included io_uring header). Then you load up the <br>
library with Panama and, if you have set up things correctly, you will <br>
see both the static inlines and the exported symbols in IO uring. (in <br>
fact, we do a similar trick to expose system library symbols like <br>
"printf" on Windows, which implements them as macros).<br>
<br>
Another (more fun?) option would be to just keep the original library, <br>
and implement the static inline functions in Java directly, using the <br>
FFM API. Most of the functions I see have only 2-3 lines in them, so it <br>
shouldn't be hard.<br>
<br>
Maurizio<br>
<br>
</blockquote></div>
</blockquote></div>