[GHC] #3242: ghci: can't load .so/.DLL for: m (addDLL: could not load DLL)

[GHC]

#3242: ghci: can't load .so/.DLL for: m (addDLL: could not load DLL)
---------------------------+------------------------------------------------
  Reporter:  jeffz1        |          Owner:         
      Type:  bug           |         Status:  new    
  Priority:  normal        |      Milestone:  7.4.3  
 Component:  GHCi          |        Version:  7.4.1  
Resolution:                |       Keywords:         
        Os:  Windows       |   Architecture:  x86    
   Failure:  None/Unknown  |     Difficulty:  Unknown
  Testcase:                |      Blockedby:         
  Blocking:                |        Related:         
---------------------------+------------------------------------------------
Changes (by nus):

  * status:  patch => new


Comment:

 Turns out that besides msvcrt also mingwex carries some actual symbols
 needed for IEEE754 compliance (f.e. 'copysignf'). When we mention libm in
 'extra-libraries'(which is not necessary), the dummy libm.a gets linked
 in, but the symbols references are satisfied by both mingwex/msvcrt. In
 the compiled case the libraries are introduced into the linkage by the
 built-in gcc specs. In the ghci case the linkage succeeds if the symbols
 references get satisfied by msvcrt (which is always preloaded by ghci),
 and fails if the symbols happen to live in mingwex (which ghci knows
 nothing about).
 Also see ticket #1883.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3242#comment:20>
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