[GHC] #8650: Unexpected behaviour of import ccall "header.h function"

[GHC]

#8650: Unexpected behaviour of import ccall "header.h function"
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       Reporter:  nh2               |             Owner:
           Type:  bug               |            Status:  new
       Priority:  normal            |         Milestone:
      Component:  Compiler          |           Version:  7.6.3
       Keywords:                    |  Operating System:  Unknown/Multiple
   Architecture:  Unknown/Multiple  |   Type of failure:  Documentation bug
     Difficulty:  Unknown           |         Test Case:
     Blocked By:                    |          Blocking:
Related Tickets:                    |
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 When I write


 {{{
 foreign import ccall "myheader.h myfunction" function :: IO ...
 }}}

 Is GHC supposed to check the existence of the header file, or do anything
 with it?

 Because I can still write {{{"myheaderBLA.h myfunction"}}} and it doesn't
 care about the first word (no error, ever, not even in linking, executable
 builds all fine).

 ----

 Relatedly, I can write

 {{{
 foreign import ccall "some.rubbish" f :: IO ...
 }}}

 and as long as {{{"some.rubbish"}}} contains a dot, nothin in the system
 will ever complain.

 carter suggested that maybe names with a dot inside are ignored by a
 linker.

 This leads me to the question: In my example above, is {{{myheaderBLA.h}}}
 actually understood as some kind of file and ignored by e.g. GHC, or is it
 a garbled symbol name? In that case, why does
 http://www.haskell.org/onlinereport/haskell2010/haskellch8.html suggest
 {{{ccall "string.h strlen"}}}? In the other case, why would it suggest
 this if the {{{"string.h"}}} part is ignored?

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8650>
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