I admit, this problem has been vexing me for some days now. From walking the return values and the contents of GetLastError, I’ve determined that this code should be working correctly according to the system. Because it clearly isn’t (it seems to enter an undefined state that inhibits the service handler from running successfully), I’ve … Read more
As far as both languages are concerned, you can basically pretend you’re trying to interface with C code. This is a complex topic, so rather than try to explain all of it, I will focus on making a simple example that you can build on using the resources linked below. First, you need to write … Read more
May be a specific example will help. Let us take the host language as Python and the guest language as C. This means that Python will be calling C functions. The first option is to write the C library in a particular way. In the case of Python the standard way would be to have … Read more
This is a known limitation of dynamic linking object files in the bytecode interpreter, GHCi. If you load compiled code that was statically linked against a given C object, and then also interpret some Haskell on the fly that also refers via the FFI to the same C object, the runtime linker will be forced … Read more
To anyone interested, this is the test case that I’ve finally got working: M.hs module Foo where foreign export ccall foo :: Int -> Int foo :: Int -> Int foo = floor . sqrt . fromIntegral test.cpp #include <iostream> #include “M_stub.h” int main(int argc, char *argv[]) { std::cout << “hello\n”; hs_init(&argc, &argv); std::cout << … Read more
I have a rich experience of using swig. SWIG claims that it is a rapid solution for wrapping things. But in real life… Cons: SWIG is developed to be general, for everyone and for 20+ languages. Generally, it leads to drawbacks: – needs configuration (SWIG .i templates), sometimes it is tricky, – lack of treatment … Read more
While not a direct answer to your original question, here’s a much more convenient way to call your function. First, make the prototype of your C function exactly as you would do it in plain C. Since you don’t need rowcount and colcount separately, I’ll collapse them into a single size parameter: void cfun(const double … Read more
Answering my own question. I fixed the ffi issue by uninstalling my faulty Ruby version and CocoaPods, then I used the -x86_64 arch to reinstall ffi and CocoaPods. These are the steps I did to get back to a working state (and to apply the M1 workarounds for ffi): Uninstall Ruby with: brew uninstall ruby … Read more
The best way to work with C strings in Rust is to use structures from the std::ffi module, namely CStr and CString. CStr is a dynamically sized type and so it can only be used through a pointer. This makes it very similar to the regular str type. You can construct a &CStr from *const … Read more