More windows woe

[Simon Peyton-Jones]

     IF_DEBUG(linker, debugBelch("Checking whether to unload " FMT_PATH "\n",

doesn't that expand to 

     IF_DEBUG(linker, debugBelch("Checking whether to unload " "%S" "\n",

What does the C compiler make of three strings in a row?  Does it automatically concatenate them? Is that ANSI C?

S

| -----Original Message-----
| From: ghc-devs [mailto:ghc-devs-bounces at haskell.org] On Behalf Of Edward
| Z. Yang
| Sent: 04 September 2013 10:15
| To: Jost Berthold
| Cc: ghc-devs
| Subject: Re: RE: More windows woe
| 
| I think this is reasonable, with the added caveat that
| the macros should be placed in includes/rts/Linker.h, because that is
| where pathchar is defined.  So how about something like:
| 
| diff --git a/includes/rts/Linker.h b/includes/rts/Linker.h
| index e900e85..871b8cd 100644
| --- a/includes/rts/Linker.h
| +++ b/includes/rts/Linker.h
| @@ -16,8 +16,10 @@
| 
|  #if defined(mingw32_HOST_OS)
|  typedef wchar_t pathchar;
| +#define FMT_PATH "%S"
|  #else
|  typedef char    pathchar;
| +#define FMT_PATH "%s"
|  #endif
| 
|  /* initialize the object linker */
| diff --git a/rts/CheckUnload.c b/rts/CheckUnload.c
| index a758b06..8dc8fdc 100644
| --- a/rts/CheckUnload.c
| +++ b/rts/CheckUnload.c
| @@ -254,7 +254,7 @@ void checkUnload (StgClosure *static_objects)
| 
|    // Mark every unloadable object as unreferenced initially
|    for (oc = unloaded_objects; oc; oc = oc->next) {
| -      IF_DEBUG(linker, debugBelch("Checking whether to unload %s\n",
| +      IF_DEBUG(linker, debugBelch("Checking whether to unload "
| FMT_PATH "\n",
|                                    oc->fileName));
|        oc->referenced = rtsFalse;
|    }
| @@ -290,11 +290,11 @@ void checkUnload (StgClosure *static_objects)
|            } else {
|                prev->next = oc->next;
|            }
| -          IF_DEBUG(linker, debugBelch("Unloading object file %s\n",
| +          IF_DEBUG(linker, debugBelch("Unloading object file " FMT_PATH
| "\n",
|                                        oc->fileName));
|            freeObjectCode(oc);
|        } else {
| -          IF_DEBUG(linker, debugBelch("Object file still in use: %s\n",
| +          IF_DEBUG(linker, debugBelch("Object file still in use: "
| FMT_PATH "\n",
|                                        oc->fileName));
|        }
|    }
| diff --git a/rts/Linker.c b/rts/Linker.c
| index 6490242..4f0a1c4 100644
| --- a/rts/Linker.c
| +++ b/rts/Linker.c
| @@ -2790,7 +2790,7 @@ unloadObj( pathchar *path )
| 
|      initLinker();
| 
| -    IF_DEBUG(linker, debugBelch("unloadObj: %s\n", path));
| +    IF_DEBUG(linker, debugBelch("unloadObj: " FMT_PATH "\n", path));
| 
|      prev = NULL;
|      for (oc = objects; oc; prev = oc, oc = next) {
| 
| Excerpts from Jost Berthold's message of Tue Sep 03 12:56:03 -0700 2013:
| > > From: Simon Peyton-Jones <simonpj at microsoft.com>
| > > To: "Edward Z. Yang" <ezyang at MIT.EDU>, Simon Marlow
| > >     <marlowsd at gmail.com>
| > > Cc: "ghc-devs at haskell.org" <ghc-devs at haskell.org>
| > > Subject: RE: More windows woe
| > > Message-ID:
| > >
| <59543203684B2244980D7E4057D5FBC1485BB7AB at DB3EX14MBXC308.europe.corp.mic
| rosoft.com>
| > >
| > > Content-Type: text/plain; charset="utf-8"
| > >
| > > Simon Marlow: please help!
| > > At the moment windows builds are hosed, which is a Bad Situation.
| > >
| > > Actually it turns out that what want is
| > >
| > >    debugBelch("Checking whether to unload %S\n", oc->fileName));
| > >
| > > That is, use "%S" rather than "%s" as format specifier for wide
| chars.
| > >
| > > Sadly, this works on Windows, but not on Linux:
| > > rts/CheckUnload.c:260:13:
| > >       error: format ?%S? expects argument of type ?wchar_t *?, but
| argument 2 has type ?pathchar *? [-Werror=format]
| > >
| > >
| > > So what I need guidance on, please!, is what the approved way to
| deal with this is.  I suppose that I could identify each use of %s on a
| filepath and say
| > >
| > > #ifdef mingw32_HOST_OS
| > >    debugBelch("Checking whether to unload %S\n", oc->fileName));
| > > #else
| > >    debugBelch("Checking whether to unload %s\n", oc->fileName));
| > > #endif
| > >
| > > But that seems deeply unsatisfactory doesn't it?
| > >
| > > If not that, then what?
| > >
| > >
| > > Simon
| >
| > Similar code is in place to distinguish between 32-bit and 64-bit
| StgWords:
| >
| >  > grep -r -e FMT_Word includes/
| > includes/stg/Types.h:#define FMT_Word32    "u"
| > includes/stg/Types.h:#define FMT_Word32    "lu"
| > includes/stg/Types.h:#define FMT_Word64    "lu"
| > includes/stg/Types.h:#define FMT_Word64    "llu"
| > includes/stg/Types.h:#define FMT_Word     FMT_Word64
| > includes/stg/Types.h:#define FMT_Word     FMT_Word32
| >
| > and format strings like "blabla " FMT_Word " ..blabla" are used inside
| > rts/. One could do the same for FMT_Path and introduce it where
| required.
| >
| > Maybe this would be acceptable?
| >
| > / Jost
| >
| 
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