dll - DLL函数上的Haskell外部导入stdcall

Question

这可能是一个非常容易回答的问题，但出于某种原因，我真的很挣扎。

我有一个用 C 语言编写的 DLL，用于在协议(protocol)级别访问硬件，我想编写一个 Haskell 程序来调用其中一些 C 函数。这是相关 C header 的片段(由于可能的版权问题，名称只是稍微混淆了):

#ifdef HWDRIVER_EXPORTS
#define HWDRIVER_API __declspec(dllexport)
#else
#define HWDRIVER_API __declspec(dllimport)
#endif
HWDRIVER_API int HW_Init(void);

这已在 Visual Studio 2003 中编译为 DLL，并且我已成功从 C 和 C# 加载 DLL，因此我确信 DLL 可以正常工作。该 DLL 被命名为“hw-driver.dll”。

接下来，这是 Haskell 源代码，只是为了测试我是否可以正确加载 DLL 并在其中调用最简单的函数:

{-# LANGUAGE ForeignFunctionInterface #-}
module Main
    where
import Foreign
import Foreign.C

foreign import stdcall "hw-driver" "HW_Init"  hwInit :: IO (CInt)

main = do
    x <- hwInit
    if x == 0 
        then putStr "Successfully initialized"
        else putStr "Could not initialize"

给我带来麻烦的线是外国进口线。据我了解，语法是外部(导入/导出)(ccall/stdcall)库名称C函数名称haskell函数名称::Haskell类型声明。所以我的应该是foreign import stdcall(因为你在Win32中加载DLL时使用stdcall)“hw-driver”(因为文件名为“hw-driver.dll”并且它与dlltest.hs位于同一目录中) “HW_Init”(C 中函数的名称) hwInit::IO (Cint)(无效参数，返回一个 int)。

但是，当我尝试运行 ghci dlltest.hs ，我得到以下输出:

[1 of 1] Compiling Main             ( dlltest.hs, interpreted )

dlltest.hs:8:43: parse error on input `"'
Failed, modules loaded: none.

第 8 行第 43 列是 HW_Init 上的第一个引号。好的，所以也许我必须将库名称和函数名称放在一个字符串中，我已经在几个地方看到过。如果我尝试运行它，那么我得到:

[1 of 1] Compiling Main             ( dlltest.hs, interpreted )

dlltest.hs:8:23: Malformed entity string
Failed, modules loaded: none.

8:23 是新字符串“hw-driver HW_Init”的第一个引号。

我不相信我的 ghc 设置 (6.10.3) 有任何问题，因为我可以在 ghci 中运行从 Real World Haskell 复制粘贴的以下代码:

{-- snippet pragma --}
{-# LANGUAGE ForeignFunctionInterface #-}
{-- /snippet pragma --}

{-- snippet imports --}
import Foreign
import Foreign.C.Types
{-- /snippet imports --}

{-- snippet binding --}
foreign import ccall "math.h sin"
     c_sin :: CDouble -> CDouble
{-- /snippet binding --}

{-- snippet highlevel --}
fastsin :: Double -> Double
fastsin x = realToFrac (c_sin (realToFrac x))
{-- /snippet highlevel --}

{-- snippet use --}
main = mapM_ (print . fastsin) [0/10, 1/10 .. 10/10]
{-- /snippet use --}

这么长的问题，我如何正确地在 Win32 DLL 上声明一个外部导入？我在谷歌上找不到任何东西。

为了在这个问题上打上标签，我能否使用像 c2hs 或 hsc2hs 这样的程序来解析头文件 hw-driver.h所以我不必为该 DLL 中包含的所有 20-25 个函数手动编写外部导入调用？我也找不到任何像样的例子。

编辑: ehemient 指出，外国进口行的正确语法是:

foreign import stdcall "hw-driver.h HW_Init" hwInit :: IO CInt

有了这个，我可以调用 ghci dlltest.hs -lhw-driver并使用成功的返回码正确调用主函数。但是，命令 ghc --make dlltest.hs -lhw-driver因链接器错误而失败。因此，这是该命令的详细输出(请注意，我在工作目录中有所有 hw-driver.{dll,h,lib} ):

Glasgow Haskell Compiler, Version 6.10.3, for Haskell 98, stage 2 booted by GHC version 6.10.1
Using package config file: C:\ghc\ghc-6.10.3\package.conf
hiding package base-3.0.3.1 to avoid conflict with later version base-4.1.0.0
wired-in package ghc-prim mapped to ghc-prim-0.1.0.0
wired-in package integer mapped to integer-0.1.0.1
wired-in package base mapped to base-4.1.0.0
wired-in package rts mapped to rts-1.0
wired-in package haskell98 mapped to haskell98-1.0.1.0
wired-in package syb mapped to syb-0.1.0.1
wired-in package template-haskell mapped to template-haskell-2.3.0.1
wired-in package dph-seq mapped to dph-seq-0.3
wired-in package dph-par mapped to dph-par-0.3
Hsc static flags: -static
*** Chasing dependencies:
Chasing modules from: *dlltest.hs
Stable obj: [Main]
Stable BCO: []
Ready for upsweep
  [NONREC
      ModSummary {
         ms_hs_date = Mon Jun 22 13:20:05 Eastern Daylight Time 2009
         ms_mod = main:Main,
         ms_imps = [Foreign.C, Foreign]
         ms_srcimps = []
      }]
compile: input file dlltest.hs
Created temporary directory: C:\DOCUME~1\CHRISC~1\LOCALS~1\Temp\/ghc4428_0
*** Checking old interface for main:Main:
[1 of 1] Skipping  Main             ( dlltest.hs, dlltest.o )
*** Deleting temp files:
Deleting: C:\DOCUME~1\CHRISC~1\LOCALS~1\Temp\/ghc4428_0/ghc4428_0.s
Warning: deleting non-existent C:\DOCUME~1\CHRISC~1\LOCALS~1\Temp\/ghc4428_0/ghc4428_0.s
Upsweep completely successful.
*** Deleting temp files:
Deleting: 
link: linkables are ...
LinkableM (Mon Jun 22 13:22:26 Eastern Daylight Time 2009) main:Main
   [DotO dlltest.o]
Linking dlltest.exe ...
*** Windres:
C:\ghc\ghc-6.10.3\bin/windres --preprocessor="C:\ghc\ghc-6.10.3\gcc" "-BC:\ghc\ghc-6.10.3\gcc-lib/" "-IC:\ghc\ghc-6.10.3\include/mingw" "-E" "-xc" "-DRC_INVOKED" --use-temp-file --input=C:\DOCUME~1\CHRISC~1\LOCALS~1\Temp\/ghc4428_0/ghc4428_0.rc --output=C:\DOCUME~1\CHRISC~1\LOCALS~1\Temp\/ghc4428_0/ghc4428_0.o --output-format=coff
*** Linker:
C:\ghc\ghc-6.10.3\gcc -BC:\ghc\ghc-6.10.3\gcc-lib/ -IC:\ghc\ghc-6.10.3\include/mingw -v -o dlltest.exe -DDONT_WANT_WIN32_DLL_SUPPORT dlltest.o -lhw-driver C:\DOCUME~1\CHRISC~1\LOCALS~1\Temp\/ghc4428_0/ghc4428_0.o -LC:\ghc\ghc-6.10.3\base-4.1.0.0 -LC:\ghc\ghc-6.10.3\integer-0.1.0.1 -LC:\ghc\ghc-6.10.3\ghc-prim-0.1.0.0 -LC:\ghc\ghc-6.10.3 -LC:\ghc\ghc-6.10.3/gcc-lib -lHSbase-4.1.0.0 -lwsock32 -lmsvcrt -lkernel32 -luser32 -lshell32 -lHSinteger-0.1.0.1 -lHSghc-prim-0.1.0.0 -lHSrts -lm -lffi -lgmp -lwsock32 -u _ghczmprim_GHCziTypes_Izh_static_info -u _ghczmprim_GHCziTypes_Czh_static_info -u _ghczmprim_GHCziTypes_Fzh_static_info -u _ghczmprim_GHCziTypes_Dzh_static_info -u _base_GHCziPtr_Ptr_static_info -u _base_GHCziWord_Wzh_static_info -u _base_GHCziInt_I8zh_static_info -u _base_GHCziInt_I16zh_static_info -u _base_GHCziInt_I32zh_static_info -u _base_GHCziInt_I64zh_static_info -u _base_GHCziWord_W8zh_static_info -u _base_GHCziWord_W16zh_static_info -u _base_GHCziWord_W32zh_static_info -u _base_GHCziWord_W64zh_static_info -u _base_GHCziStable_StablePtr_static_info -u _ghczmprim_GHCziTypes_Izh_con_info -u _ghczmprim_GHCziTypes_Czh_con_info -u _ghczmprim_GHCziTypes_Fzh_con_info -u _ghczmprim_GHCziTypes_Dzh_con_info -u _base_GHCziPtr_Ptr_con_info -u _base_GHCziPtr_FunPtr_con_info -u _base_GHCziStable_StablePtr_con_info -u _ghczmprim_GHCziBool_False_closure -u _ghczmprim_GHCziBool_True_closure -u _base_GHCziPack_unpackCString_closure -u _base_GHCziIOBase_stackOverflow_closure -u _base_GHCziIOBase_heapOverflow_closure -u _base_ControlziExceptionziBase_nonTermination_closure -u _base_GHCziIOBase_blockedOnDeadMVar_closure -u _base_GHCziIOBase_blockedIndefinitely_closure -u _base_ControlziExceptionziBase_nestedAtomically_closure -u _base_GHCziWeak_runFinalizzerBatch_closure -u _base_GHCziTopHandler_runIO_closure -u _base_GHCziTopHandler_runNonIO_closure -u _base_GHCziConc_runHandlers_closure -u _base_GHCziConc_ensureIOManagerIsRunning_closure
Reading specs from C:/ghc/ghc-6.10.3/gcc-lib/specs
Configured with: ../gcc-3.4.5-20060117-3/configure --with-gcc --with-gnu-ld --with-gnu-as --host=mingw32 --target=mingw32 --prefix=/mingw --enable-threads --disable-nls --enable-languages=c,c++,f77,ada,objc,java --disable-win32-registry --disable-shared --enable-sjlj-exceptions --enable-libgcj --disable-java-awt --without-x --enable-java-gc=boehm --disable-libgcj-debug --enable-interpreter --enable-hash-synchronization --enable-libstdcxx-debug
Thread model: win32
gcc version 3.4.5 (mingw-vista special r3)
 C:/ghc/ghc-6.10.3/gcc-lib/collect2.exe -Bdynamic -o dlltest.exe -u _ghczmprim_GHCziTypes_Izh_static_info -u _ghczmprim_GHCziTypes_Czh_static_info -u _ghczmprim_GHCziTypes_Fzh_static_info -u _ghczmprim_GHCziTypes_Dzh_static_info -u _base_GHCziPtr_Ptr_static_info -u _base_GHCziWord_Wzh_static_info -u _base_GHCziInt_I8zh_static_info -u _base_GHCziInt_I16zh_static_info -u _base_GHCziInt_I32zh_static_info -u _base_GHCziInt_I64zh_static_info -u _base_GHCziWord_W8zh_static_info -u _base_GHCziWord_W16zh_static_info -u _base_GHCziWord_W32zh_static_info -u _base_GHCziWord_W64zh_static_info -u _base_GHCziStable_StablePtr_static_info -u _ghczmprim_GHCziTypes_Izh_con_info -u _ghczmprim_GHCziTypes_Czh_con_info -u _ghczmprim_GHCziTypes_Fzh_con_info -u _ghczmprim_GHCziTypes_Dzh_con_info -u _base_GHCziPtr_Ptr_con_info -u _base_GHCziPtr_FunPtr_con_info -u _base_GHCziStable_StablePtr_con_info -u _ghczmprim_GHCziBool_False_closure -u _ghczmprim_GHCziBool_True_closure -u _base_GHCziPack_unpackCString_closure -u _base_GHCziIOBase_stackOverflow_closure -u _base_GHCziIOBase_heapOverflow_closure -u _base_ControlziExceptionziBase_nonTermination_closure -u _base_GHCziIOBase_blockedOnDeadMVar_closure -u _base_GHCziIOBase_blockedIndefinitely_closure -u _base_ControlziExceptionziBase_nestedAtomically_closure -u _base_GHCziWeak_runFinalizzerBatch_closure -u _base_GHCziTopHandler_runIO_closure -u _base_GHCziTopHandler_runNonIO_closure -u _base_GHCziConc_runHandlers_closure -u _base_GHCziConc_ensureIOManagerIsRunning_closure C:/ghc/ghc-6.10.3/gcc-lib/crt2.o C:/ghc/ghc-6.10.3/gcc-lib/crtbegin.o -LC:\ghc\ghc-6.10.3\base-4.1.0.0 -LC:\ghc\ghc-6.10.3\integer-0.1.0.1 -LC:\ghc\ghc-6.10.3\ghc-prim-0.1.0.0 -LC:\ghc\ghc-6.10.3 -LC:\ghc\ghc-6.10.3/gcc-lib -LC:/ghc/ghc-6.10.3/gcc-lib dlltest.o -lhw-driver C:\DOCUME~1\CHRISC~1\LOCALS~1\Temp\/ghc4428_0/ghc4428_0.o -lHSbase-4.1.0.0 -lwsock32 -lmsvcrt -lkernel32 -luser32 -lshell32 -lHSinteger-0.1.0.1 -lHSghc-prim-0.1.0.0 -lHSrts -lm -lffi -lgmp -lwsock32 -lmingw32 -lgcc -lmoldname -lmingwex -lmsvcrt -luser32 -lkernel32 -ladvapi32 -lshell32 -lmingw32 -lgcc -lmoldname -lmingwex -lmsvcrt C:/ghc/ghc-6.10.3/gcc-lib/crtend.o
C:\ghc\ghc-6.10.3\gcc-lib\ld.exe: cannot find -lhw-driver
collect2: ld returned 1 exit status
*** Deleting temp files:
Deleting: C:\DOCUME~1\CHRISC~1\LOCALS~1\Temp\/ghc4428_0/ghc4428_0.o C:\DOCUME~1\CHRISC~1\LOCALS~1\Temp\/ghc4428_0/ghc4428_0.rc
*** Deleting temp dirs:
Deleting: C:\DOCUME~1\CHRISC~1\LOCALS~1\Temp\/ghc4428_0

事实证明，实际的链接并不像我想象的那么困难。我正在使用 foreign import stdcall 我认为在 Visual Studio 2003 中构建的 DLL 是正确的。我必须下载 pexports MinGW 的工具，它列出了从 DLL 导出的函数。链接器一直在寻找 HWInit@0，但是 pexports说 DLL 只导出 HWInit。

我将线路更改为 foreign import ccall 相反，我成功地能够使用 ghc --make dlltest.hs hw-driver.lib 中的任何一个链接程序或 ghc --make dlltest.hs -L. -lhw-driver由于在工作目录中同时存在 .lib 和 .dll 文件。

Answer 1

FFI spec # 4.1.1 Import Declarations ,

impent → " [static] [chname] [&] [cid] "
            | " dynamic "
            | " wrapper "

其中 chname 是“C header 名称”，而不是“库名称”。

FFI spec # 4.1.4 Specification of Header Files

A C header specified in an import declaration is always included by #include "chname". There is no explicit support for #include <chname> style inclusion. The ISO C99 [3] standard guarantees that any search path that would be used for a #include <chname> is also used for #include "chname" and it is guaranteed that these paths are searched after all paths that are unique to #include "chname". Furthermore, we require that chname ends on .h to make parsing of the specification of external entities unambiguous.

尝试使用正确的标题名称，

foreign import stdcall "hw-driver.h HW_Init" hwInit :: IO CInt

或者根本没有标题名称。

foreign import stdcall "HW_Init" hwInit :: IO CInt

您的命令行似乎不包含 .作为库搜索路径。这很可能是问题所在。 GHCI 神奇地包含 .在库搜索路径中。

ghc --make dlltest.hs -L。 -lhwdriver

如果仍然失败，则可能是导致问题的静态库。不太可能，但是...

Windows 上的 GHC 默认使用动态链接。既然你有 .lib ，这是一个静态库，请尝试通知链接器您想要静态链接。

ghc --make dlltest.hs -L。 -optl-Bstatic -lhwdriver -optl-Bdynamic


至于自动生成的绑定(bind)，有

Green Card

C->Haskell

hsc2hs

我发现 c2hs 是最容易使用的，但我从未在需要 stdcall 的任何东西上尝试过它。 s。

写完 foreign 没那么麻烦手动的东西，如果只有 25 个电话左右。我设法手动将绑定(bind)写入 libvlc几年前，为了一些小项目......