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Let's consider an example:

We have a haskell package with some C code imported in haskell:

// a.h file
int get_something(void);

// a.c file
#include "a.h"
int get_something(void) { return 42; }

// M.hs file
module M where

foreign import ccall "a.h get_something" :: IO Int

The problem here is we can't mix that package with other packages having global 'get_something' symbol.

Sometimes it happens when a package copies part of implementation from another package with .c bits under different haskell namespace. Haskell parts would coexist freely, but not C symbols.

Would be great if ghc would export some unique package identifier in a way C code could attach it to all exported symbols making linking possible.

Something like that:

// a.h file
#include "HsFFI.h" /* #define FOR_HASKELL(__sym) package_id_##__sym */
int FOR_HASKELL(get_something)(void);

// a.c file
#include "a.h"
int FOR_HASKELL(get_something)(void) { return 42; }

// M.hs file
module M where

foreign import ccall-for-haskell "a.h get_something" :: IO Int

That way we explicitly mark symbol as inaccessible to external plain C code.

Trac metadata

Trac field	Value
Version	7.8.3
Type	FeatureRequest
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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