Its easy to use for users, cause the header file is very easy to find from library source code. Provided luajit supports your platform, it will be as fast if not faster than writing c extensions. The code generated by the jitcompiler for accesses to c data structures from lua code is on par with the code a c compiler would generate. One major advantage of the luajit ffi is that you are now able to write those wrappers in lua. Simple c function and structure declarations are directly understood. The finalizer can be a lua function or a cdata function or cdata function pointer. Luaradio blocks are written in pure lua, but can use luajits ffi to wrap external libraries, like volk, liquiddsp, and others, for computational acceleration, sophisticated processing, and interfacing with sdr hardware. This decision opens up all sorts of possibilities for extensions through. These are supported by luajits ffi and will not be supported by this. The bindings will still work with lua vms that dont have the ffi extension by falling back to using the standard lua c api. Speed easier bindings done from the lua side, given a simple c abi of whatever needs binding. Ive worked out the module loading system and have luajit linked in to my game moduledll, and can all and run lua code.
Please note that most developers prefer to only bind to the few library calls they actually need. It is designed to be interface compatible with the ffi library in luajit see. Luajits builtin ffi provides a very fast way for lua programs to access c functions and structures. I always liked how the luajit ffi worked, so i decided to roughly recreate it, but in a portable way, using libffi, so that it works on anything as. Rewrite printc in lua using the ffi, or write lua c api bindings to the library youre using p. The only annoying thing is its lack of standard libraries. The ffi is disabled, too, since its not very useful in such an environment. The luaffifb project seems generally dead and nonportable, while alien doesnt provide any sort of fancy interface, and im not aware of any others.
Lua luajit more than 3 years have passed since last update. This is a library for calling c function and manipulating c types from lua. These new lua bindings add optional support for luajit2s new ffi extension. One of these additional modules is its ffi library, which aims to allow easy access to c functions and data. Many of the simpler c functions can probably be used directly from your lua code, without any wrappers. Its strongly suggested to build luajit separately using the supplied build system. At runtime you pass it some c function definitions, and then everything youve defined becomes callable, and these calls are subsequently jit compiled in the most efficient way possible. See the luaradio mailing list for general discussion. Windows support would be even better if someone else contributed this, since i dont run windows. Luajit offers a very fast script interpreter and justintime compiler, in addition to several extensions to the base lua api. So heres something to pop up a message box on windows. Here we have a ffibinding which means that only the header of the c functions are sufficient for the ffi library to handle all conversions of variables to and from the lua. Whats happening is that the application is giving a bad callback error shortly after the application starts, especially when moving the.
Browse other questions tagged c, ffi, lua, luajit you may be interested in these books. And at a fraction of the time it would cost you to create an extra c module using the luac api. Luajit s builtin ffi provides a very fast way for lua programs to access c functions and structures. May 15, 2016 there are obvious upsides to using luajit. Here were wrapping the call to the c function in a lua. Heres a simple example for embedding lua or luajit into your application. The luausers wiki lists many usercontributed addons for lua.
Aug 28, 2014 luv is a lua bindung for the libuv library which means that it uses all the c api provided by the lua language to code the interface between c functions and lua functions. Extending lua to c using the luajit ffi library search. On the other hand, the call to those functions should be made through a library that actually implement those functions, such as openssl, not ffi. Luajit and puc lua appear to be very similar superficially luajit is lua, but fast. Extending lua to c using the luajit ffi library i did a. Luajit is meant to be a dropin replacement for stock lua, so it should work just by replacing it. This allows directly binding c libraries to lua without having to write bindings in c. The example in luajit ffi shows luajit ffi call is 110x faster than in pure lua interpreter.
Luajit is a justintime compiler jit for the lua programming language. The foreign function interface ffi present in the latest beta releases of luajit is really nice for when you need to do things outside the lua world. Hi, im thinking about using luajits ffi in the next lupa release to provide access to cpythons buffer interface. Precompiled lua libraries and executables are available at luabinaries. On the other hand, the call to those functions should be made through a library that actually implement. Tags c, ffi, lua, luajit not what youre looking for. Hi all, just thought i would share how i have made luasocket work with stingray in windows. Here we have a ffi binding which means that only the header of the c functions are sufficient for the ffi library to handle all conversions of variables to and from the lua.
The ffi library largely obviates the need to write tedious manual luac bindings in c. Luajit and python support copynpasting c header file when defining function signatures. Stingrays a win64 application so your dll needs to be compiled for win 64. Luajit extends lua with a powerful ffi interface that allows calling c functions directly, without the need to write glue code. Lua is a powerful, dynamic and lightweight programming language. This would allow direct lowlevel access to numpy matrices and the like, thus providing an efficient lua companion for the huge set of scientific computation libraries in scipy, sage and the like. Given that the ffi library is designed to interface with c code and that declarations. As there seem little to no luajit binaries anywhere on the web, i decided to put some up myself. The advantages of luajit over puc lua seem to be performance and its ffi. The build went through with no errors and the jit seems to just work just fine.
Now, these buffers are basically represented as a struct containing a void. Extending lua to c using the luajit ffi library hi, my guess is that youve compiled your dll for a windows 32 target. On windows systems, this binds to symbols exported from the. If youve already embedded lua into your application, you probably dont need to do anything to switch to luajit, except link with a different library. The problem is, ffi only searches for symbols in the. Luajits bit, ffi and jit modules luajits extensions from lua 5. The ffi library is tightly integrated into luajit its not available as a separate module.
I recently looked into lua and it seems really nice. All discussions only photos only videos only links only polls only events only. The lua users wiki lists many usercontributed addons for lua. Calls to c functions can be inlined in jitcompiled code, unlike calls to functions bound via the classic luac api. If you didnt install in luajit directory, set basedir variable in imgui. Tonight i did some more modeling and discovered that sandbags and sandbag walls and bunkers are hella hard. Luajit ffi binding to libuv with coroutines hacker. An existing finalizer can be removed by setting a nil finalizer, e. Mar 07, 2014 tonight i did some more modeling and discovered that sandbags and sandbag walls and bunkers are hella hard. No unexpected code being generated that may present edgecase bugs which might be difficult to detect. The following api functions return information about c types. Add lua and lua\jit directories below it and copy all lua files from the src\jit directory. Ive searched around and found that therere really little document on the ffi module. Extending lua to c using the luajit ffi library the runtime lua environment hosted by the stingray engine is powered by the luajit library.
The lua c calling overhead is basically the same as a c c call. But with the jit compiler comes along a nice ffi c interface. And the endless loop protection is, by definition, incomplete, as luajit cannot protect against that. The lua c api and the luajit ffi are deliberately separated and cannot interact.
Net command prompt, change to the directory where msvcbuild. How i get the cdata out in c function with variable arguments. Until recently it did not dawn on me what a brilliant decision the stingray team made by using luajit for their lua implementation. The luajit wiki has been created to gather community resources about developing programs using luajit. Rewrite printc in lua using the ffi, or write lua c api bindings to the library youre using p with. Discuss github, using source code to modify the engine, and the creation of engine plugins. Luajit has an ffi which allows code to be jit compiled, whereas regular c api calls arent 1.
Depending on your distribution, you may need to install a package for gcc, the. Some minor concessions are needed for smoother interoperation with lua. You would need to add the definition of those data types as well. Luajit ffi bindings for libiconv character encoding conversion in openresty xiaooloong lua restyiconv.
Feedback appreciated to email protected, or the luajit mailing list. The relative bug counts reinforce the fact that in the details, the two implementations are very different for example, luajit uses a lot of assembly language while puc lua is pure c89. Lua is implemented in pure ansi c and compiles unmodified in all platforms that have an ansi c compiler. Its considerably faster than plain lua up to a hundred times faster and it comes with a really nice way of loading shared libraries through its ffi library. Extending lua to c using the luajit ffi library autodesk.
1541 1650 546 1443 944 131 1188 1167 1035 49 1665 467 387 1608 1190 416 1104 1322 439 751 1061 1380 565 173 403 664 1159 1268 619 1170 919 1072 53 301 789 693 468 865 558 1393