使用haskell构建动态库并从C ++中使用它

问题描述

我想建立一个包含haskell函数的动态库。我在linux上工作，想从C ++代码调用这个动态库。

我使用，并具有以下文件：

Test.hs：

  { - ＃LANGUAGE ForeignFunctionInterface＃ - } 
模块测试其中
 
 import Foreign.C.Types 
 
 hsfun :: CInt  - > IO CInt 
 hsfun x = do 
 putStrLnHello World
 return（42 + x）
 
外部导出ccall 
 hsfun :: CInt  - ; IO CInt 
  

module_init.c：

  #define CAT（a，b）XCAT（a，b）
 #define XCAT（a，b）a ## b 
 #define STR （a）
 #define XSTR（a）#a 
 
 #include< HsFFI.h> 
 
 extern void CAT（__stginit_，MODULE）（void）; 
 
 static void library_init（void）__attribute__（（constructor））; 
 static void 
 library_init（void）
 {
 / *这似乎是一个无操作，但它使GHCRTS envvar工作。 * / 
 static char * argv [] = {STR（MODULE）.so，0}，** argv_ = argv; 
 static int argc = 1; 
 
 hs_init（& argc，& argv_）; 
 hs_add_root（CAT（__stginit_，MODULE））; 
} 
 
 static void library_exit（void）__attribute__（（destructor））; 
 static void 
 library_exit（void）
 {
 hs_exit（）; 
} 
  

现在我将这个文件编译为动态库：

  $ ghc -dynamic -shared -fPIC -optc'-DMODULE = Test'Test.hs module_init.c -o libTest.so 
 [ 1 of 1]编译测试（Test.hs，Test.o）
链接libTest.so ... 
  

这会创建文件Test_stub.h：

  #includeHsFFI.h
 #ifdef __cplusplus 
 externC{
 #endif 
 extern HsInt32 hsfun（HsInt32 a1）; 
 #ifdef __cplusplus 
} 
 #endif 
  

和Test_stub。 c：

  #define IN_STG_CODE 0 
 #includeRts.h
 #include h
 #ifdef __cplusplus 
 externC{
 #endif 
 
 extern StgClosure Test_zdfhsfunzua165_closure; 
 HsInt32 hsfun（HsInt32 a1）
 {
 Capability * cap; 
 HaskellObj ret; 
 HsInt32 cret; 
 cap = rts_lock（）; 
 cap = rts_evalIO（cap，rts_apply（cap，（HaskellObj）runIO_closure，rts_apply（cap，& Test_zdfhsfunzua165_closure，rts_mkInt32（cap，a1））），& ret）; 
 rts_checkSchedStatus（hsfun，cap）; 
 cret = rts_getInt32（ret）; 
 rts_unlock（cap）; 
 return cret; 
} 
 static void stginit_export_Test_zdfhsfunzua165（）__attribute __（（constructor））; 
 static void stginit_export_Test_zdfhsfunzua165（）
 {getStablePtr（（StgPtr）& Test_zdfhsfunzua165_closure）;} 
 #ifdef __cplusplus 
} 
 #endif 
  
 
 
 
然后我创建一个cpp文件main.cpp：
  #includeTest_stub.h
 
 #include< iostream> 
 
 using namespace std; 
 
 int main（）
 {
 cout< hsfun（5）; 
} 
  
并希望编译和链接。但是当我调用g ++，它说：
  $ g ++ -I / usr / lib / ghc-7.0.3 / L. -lTest main.cpp 
 /tmp/ccFP2AuB.o：在函数`main'中：
 main.cpp :(。text + 0xa）：undefined对`hsfun'的引用
 collect2：ld gab 1 als Ende-Statuszurück
  
所以我添加了Test_stub.o文件到命令行我认为hsfun函数应该已经在libTest.so中通过-lTest参数添加了我不认为，我应该链接到可执行文件的Test_stub.o文件，因为我想使用动态链接，但这个也不工作：
  $ g ++ -I / usr / lib / ghc-7.0.3 / include -L。 -lTest main.cpp Test_stub.o 
 Test_stub.o：在函数`hsfun'中：
 Test_stub.c :(。text + 0x9）：未定义对`rts_lock'的引用
 Test_stub.c （。text + 0x16）：未定义引用`rts_mkInt32'
 Test_stub.c :(。+ 0x1d）：未定义的引用`Test_zdfhsfunzua165_closure'
 Test_stub.c :(。未定义的引用`rts_apply'
 Test_stub.c :(。text + 0x2f）：未定义引用`base_GHCziTopHandler_runIO_closure'
 Test_stub.c :( .text + 0x3a）：未定义`rts_apply'引用
 Test_stub.c :(。text + 0x4a）：未定义的引用`rts_evalIO'
 Test_stub.c :(。text + 0x5c）：未定义的引用`rts_checkSchedStatus'
 Test_stub.c :(。 
 test_stub.c :(。text + 0x70）：未定义的引用`rts_unlock'
 Test_stub.o：在函数`stginit_export_Test_zdfhsfunzua165'中：
 Test_stub.c :( .text.startup + 0x3）：未定义的引用`Test_zdfhsfunzua165_closure'
 Test_stub.c :( .text.startup + 0x8）：未定义引用`getStablePtr'
 collect2：ld gab 1 als Ende-Statuszurück
  
我必须链接Test_stub.o吗？如果是，为什么？ 
解决方案
可能比g ++更容易让ghc做工作， p> 
 
 
在创建共享库之后为我完成了这项工作。我已经测试了它与7.2.2和7.0.2，都在这里工作。
 
I want to build a dynamic library containing haskell functions. I work on linux and want to call this dynamic library from C++ code.
I used the example at http://wiki.python.org/moin/PythonVsHaskell and have the following files:
Test.hs:
{-# LANGUAGE ForeignFunctionInterface #-}
module Test where

import Foreign.C.Types

hsfun :: CInt -> IO CInt
hsfun x = do
    putStrLn "Hello World"
    return (42 + x)

foreign export ccall
    hsfun :: CInt -> IO CInt
module_init.c:
#define CAT(a,b) XCAT(a,b)
#define XCAT(a,b) a ## b
#define STR(a) XSTR(a)
#define XSTR(a) #a

#include <HsFFI.h>

extern void CAT (__stginit_, MODULE) (void);

static void library_init (void) __attribute__ ((constructor));
static void
library_init (void)
{
  /* This seems to be a no-op, but it makes the GHCRTS envvar work. */
  static char *argv[] = { STR (MODULE) ".so", 0 }, **argv_ = argv;
  static int argc = 1;

  hs_init (&argc, &argv_);
  hs_add_root (CAT (__stginit_, MODULE));
}

static void library_exit (void) __attribute__ ((destructor));
static void
library_exit (void)
{
  hs_exit ();
}
Now I compile this files to a dynamic library:
$ ghc -dynamic -shared -fPIC -optc '-DMODULE=Test' Test.hs module_init.c -o libTest.so
[1 of 1] Compiling Test             ( Test.hs, Test.o )
Linking libTest.so ...
This creates among other things the file Test_stub.h:
#include "HsFFI.h"
#ifdef __cplusplus
extern "C" {
#endif
extern HsInt32 hsfun(HsInt32 a1);
#ifdef __cplusplus
}
#endif
and Test_stub.c:
#define IN_STG_CODE 0
#include "Rts.h"
#include "Stg.h"
#ifdef __cplusplus
extern "C" {
#endif

extern StgClosure Test_zdfhsfunzua165_closure;
HsInt32 hsfun(HsInt32 a1)
{
Capability *cap;
HaskellObj ret;
HsInt32 cret;
cap = rts_lock();
cap=rts_evalIO(cap,rts_apply(cap,(HaskellObj)runIO_closure,rts_apply(cap,&Test_zdfhsfunzua165_closure,rts_mkInt32(cap,a1))) ,&ret);
rts_checkSchedStatus("hsfun",cap);
cret=rts_getInt32(ret);
rts_unlock(cap);
return cret;
}
static void stginit_export_Test_zdfhsfunzua165() __attribute__((constructor));
static void stginit_export_Test_zdfhsfunzua165()
{getStablePtr((StgPtr) &Test_zdfhsfunzua165_closure);}
#ifdef __cplusplus
}
#endif
Then I create a cpp file main.cpp:
#include "Test_stub.h"

#include <iostream>

using namespace std;

int main()
{
    cout << hsfun(5);
}
and want to compile and link it. But when I call g++, it says:
$ g++ -I/usr/lib/ghc-7.0.3/include -L. -lTest main.cpp
/tmp/ccFP2AuB.o: In function `main':
main.cpp:(.text+0xa): undefined reference to `hsfun'
collect2: ld gab 1 als Ende-Status zurück
So I added the Test_stub.o file to the command line (although I think the hsfun function should already be defined in libTest.so which is added via the -lTest parameter. I don't think, I should link the Test_stub.o file into the executable because I want to use dynamic linking), but this also doesn't work:
$ g++ -I/usr/lib/ghc-7.0.3/include -L. -lTest main.cpp Test_stub.o
Test_stub.o: In function `hsfun':
Test_stub.c:(.text+0x9): undefined reference to `rts_lock'
Test_stub.c:(.text+0x16): undefined reference to `rts_mkInt32'
Test_stub.c:(.text+0x1d): undefined reference to `Test_zdfhsfunzua165_closure'
Test_stub.c:(.text+0x28): undefined reference to `rts_apply'
Test_stub.c:(.text+0x2f): undefined reference to `base_GHCziTopHandler_runIO_closure'
Test_stub.c:(.text+0x3a): undefined reference to `rts_apply'
Test_stub.c:(.text+0x4a): undefined reference to `rts_evalIO'
Test_stub.c:(.text+0x5c): undefined reference to `rts_checkSchedStatus'
Test_stub.c:(.text+0x66): undefined reference to `rts_getInt32'
Test_stub.c:(.text+0x70): undefined reference to `rts_unlock'
Test_stub.o: In function `stginit_export_Test_zdfhsfunzua165':
Test_stub.c:(.text.startup+0x3): undefined reference to `Test_zdfhsfunzua165_closure'
Test_stub.c:(.text.startup+0x8): undefined reference to `getStablePtr'
collect2: ld gab 1 als Ende-Status zurück
Do I have to link the Test_stub.o? If yes, why? And which arguments should I pass to the linker?
 解决方案 
Probably easier than wrestling with g++ is letting ghc do the work,
did the job for me after creating the shared lib the way you did. I have tested it with 7.2.2 and 7.0.2, both worked here.
                        
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