On 2010-10-05 10:02:45 -0400, Heywood Floyd <[email protected]> said:
But, sometimes I get reeeaally weird bugs. I had one bug where if I
added an empty function to a class in D I got EXC_BAD_ACCES (segfault).
An empty function! Ie "void f(){}". Remove the function--it works. In
the debugger, I got the impression maybe the stack has got messed up,
but I don't know, the debugger just shows assembler code, and I don't
have the proper skills.
It's hard to say without further details, but it could be that you're
not recompiling everything that uses the class where you add a
function. Unlike in Objective-C, adding a function to a D class breaks
most compiled code that uses that class (because you're adding an
offset to the virtual function table), so you need to recompile every D
module that uses that class (or a derived class).
Note that this is totally unrelated to having Objective-C code in the
same program.
This got really frustrating, needless to say, so I started playing
around with the build settings. I switched from using LLVM 1.5 (for the
obj-c code) to gcc 4.2. And now it magically seems to work!
Are you using D for Xcode? By doing that you basically force everything
to be recompiled, which solves problem described above.
[...]
== Question ==
How do you make D code and Obj-C code coexist? That is, I want to write
a Cocoa-app that is mostly written in D, and with a little "glue"-code
in Objective-C. How do you set that up? Is it even supposed to be
possible?
It is totally possible, and not that hard. Communicating via `extern
(C)` functions should work well.
(And what could the bug above be? I know LLVM does link-time
optimizations, and even run-time optimizations. Could it be that it
messes things up?)
I doubt LLVM optimizations have anything to do with your problem.
Things to keep in mind when mixing Objective-C:
1. Apple's Objective-C GC isn't supported by D, so you it's probably
safer to use manual memory management (retain/release) on the
Objective-C site.
2. Exceptions are not compatible between the two runtimes. Throwing can
cause unexpected results when it unwinds stack frames in the other
language.
--
Michel Fortin
[email protected]
http://michelf.com/
