Unknown symbol `_environ' on MacOS X
Shared libraries and bundles on MacOS X Leopard don't have direct access to environ (i.e. extern char **environ), which is only available to the loader ld when a complete program is being linked. If direct access to environ is needed, the _NSGetEnviron() routine, defined in <crt_externs.h> can be used to retrieve the address of environ at runtime (man environ(7) see last paragraph in section PROGRAMMING).
Two Libraries are affected by this - namely base and unix. Both of these Libraries implement (duplicate code) access to environ:
* ToDo: write a feature test that doesn't assume 'environ' to
* be in scope at link-time. */
extern char** environ;
INLINE char **__hscore_environ() { return environ; }extern char **environ;Unfortunately this does not work on MaxOS X Leopard with XCode 3.0. My temporary workaround was to comment out the current definition of environ in the header files and add the following instead:
- Hack for base/include/HsBase.h:
/* ToDo: write a feature test that doesn't assume 'environ' to
* be in scope at link-time. */
//extern char **environ;
//INLINE char **__hscore_environ() { return environ; }
#include <crt_externs.h>
INLINE char **__hscore_environ(void) { return (*_NSGetEnviron()); }- Hack for unix/include/HsUnix.h:
//extern char **environ;
#include <crt_externs.h>
INLINE char **__hsunix_environ (void) { return (*_NSGetEnviron()); }- Hack for unix/System/Posix/Env.hsc:
--getEnvironmentPrim :: IO [String]
--getEnvironmentPrim = do
-- c_environ <- peek c_environ_p
-- arr <- peekArray0 nullPtr c_environ
-- mapM peekCString arr
--
--foreign import ccall unsafe "&environ"
-- c_environ_p :: Ptr (Ptr CString)
getEnvironmentPrim :: IO [String]
getEnvironmentPrim = do
c_environ <- c_environ_p
arr <- peekArray0 nullPtr c_environ
mapM peekCString arr
foreign import ccall unsafe "__hsunix_environ"
c_environ_p :: IO (Ptr CString)Unfortunately I do not know GHC well enough to propose a clean patch. With these 'hacks' ghc compiled from source on MacOS X Leopard with XCode 3.0 works well. It would also probably be good to get rid of the code duplication in the base and unix libraries.
Shall I open another Ticket for libraries/unix?
References:
Trac metadata
| Trac field | Value |
|---|---|
| Version | 6.9 |
| Type | Bug |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | libraries/base |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | igor@bytelabs.org |
| Operating system | |
| Architecture |