Re: [Haskell-cafe] OSX, ghci, dylib, what is the correct way?

On Sun, Jun 12, 2011 at 11:45 AM, Brandon Allbery wrote:

On Sun, Jun 12, 2011 at 14:31, Jason Dagit wrote:

...

If I build the C library as a .a, then ghci comlains that it cannot open the .dylib.  My first question is: Why does ghci need a .dylib and does it really use it?

Static libraries are... static.  ghci would have to rebuild itself against the static archive to use it; that's how static archives work.  Dynamic libraries are dynamic because they can be loaded at runtime instead of compile time.

Interesting. When I use dtruss to see what files ghci opens, it definitely opens .a files. That gave me the impression it knows how to open a .a and use it at run-time.

...

When I build a dylib I get a [segfault when loading the code into ghci][2].

I believe ghci still uses its own dynamic loader instead of the standard library one, and as such it doesn't handle everything quite correctly; Mach-O is a moving target and Apple doesn't always document its changes.[1]  When you compile, the system linker is used to build the executable and things work properly.

[1] http://hackage.haskell.org/trac/ghc/ticket/4244

It's hard for me to make sense of that ticket with so little context. This comment seems to go against what you're saying: Changed 10 months ago by igloo milestone set to 6.16.1 The best way to achieve this is probably to switch to using dynamic libraries for GHCi. Thanks, Jason