Re: Dynamic loading problem

Hi, I was playing with dynamically loaded modules and had the same problem. It has nothing to do with shared objects. What you have to do is to force the main program (the one that loads the loadable modules) to explicitly link all of the object files that the set {<main program>, <loadable modules>} depends on. For example, if a module depends on symbols in /HShaskell98.o, (but the main program doesn't), you should explicit link /HShaskell98.o into the main program. This happens because when you build your loadable modules the linker assumes that they will later be linked into a main program, at which time all of the undefined references will be resolved. Since you never link the modules and main together, some references remain unresolved. It shouldn't be hard to automate this; a script could run nm on the module and main program, make a list of unresolved references, search the files in to know which object to include, and then relink the main program. If you look at the makefiles in http://www.algorithm.com.au/wiki/hacking/haskell.ghc_runtime_loading you'll see some examples of how the main program has to be linked. Best Wishes, Greg On Apr 29, 2004, at 3:24 PM, Hampus Ram wrote:

On Thu, Apr 29 2004, Alastair Reid wrote:

...

Does passing the flag RTLD_GLOBAL to dlopen help? (man dlopen for info about this flag)

No, since none of the objects involved are shared objects (I use neither dlopen or addDLL but the loadObj function). They are just compiled Haskell modules and the problem lies in the RTS symbols which for some reason can't be loaded dynamically (why it doesn't work when the base package etc. can be loaded is beyond me).

However when loading shared objects your flag is the one to use. That works without flaw and is really a nicer way to load shared objects than the RTS function addDLL.

/Hampus

-- Homepage: http://www.dtek.chalmers.se/~d00ram E-mail: d00ram@dtek.chalmers.se

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