我试图从 C++ Win32 控制台应用程序的空 C dll 中调用函数 long *Test(int)。该 dll 称为 QSIWrapperUMeLt.dll。当我尝试构建控制台应用程序时，我得到以下输出：
adding resource. type:MANIFEST, name:1, language:0x0409, flags:0x30, size:406
1>TestPlatform.obj : error LNK2019: unresolved external symbol _Test referenced in function _wmain
1>C:\Users\Deven Bryant\Desktop\temp version\TestPlatform\Debug\TestPlatform.exe : fatal error LNK1120: 1 unresolved externals
1>
1>Build FAILED.
这是我为了从我的控制台应用程序调用我的 QSIWrapperUMeLt dll 所做的；在 dll 中，我在函数定义中包含了extern "C"and__declspec(dllexport)属性。dll 和控制台应用程序都设置为为 Win32 构建。我已确保在项目设置中将 dll 设置为编译为 c 代码。在控制台应用程序中，我已经#includedQSIWrapperUMeLt.h文件并更改__declspec(dllexport)为__declspec(dllimport)使用预处理器指令。我还使用 .dll 链接到 dll #pragma comment(lib, "DLLTutorial.lib")。QSIWrapperUMeLt 库文件、头文件和 dll 位于我的控制台应用程序的项目文件夹中。
下面我提供了 dll 的头文件、控制台应用程序 cpp 文件以及在 QSIWrapperUMeLt.dll 上运行时由 dumpbin 检测到的符号表和导出函数。
另外，我尝试了显式链接路由，但是当我调用加载库时，它返回一个空指针。
关于我做错了什么的任何想法将不胜感激。
QSIWrapperUMELt.h
#include <Windows.h>
//#pragma comment(lib, "DLLTutorial.lib")
#ifdef EXPORT
#define DECLSPEC __declspec(dllexport)
#else
#define DECLSPEC __declspec(dllimport);
#endif
#define BOOL int
#define TRUE 1
#define FLSE 0
typedef enum
{
initialize = 0,
setup,
capture,
temperature,
close,
getimagedata
} CallStates;
typedef struct ReturnedValues
{
BOOL initialized, imagereadyflag, exposuredone;
long** imagedata;
double Temperature;
}ReturnedValues;
typedef struct CameraData
{
short Mode;
short Binning;
int Exposure;
int Top;
int Left;
int Height; //ROIH
int Width; //ROIW
int CoolerSetpoint;
int Temperature;
}CameraData;
typedef void (*callFunction)(CameraData camdata, ReturnedValues *retvals);
DECLSPEC ReturnedValues *retvals;
callFunction pcallFunction;
HINSTANCE hlib;
CameraData camdata;
#ifdef __cplusplus
extern "C"
{
#endif
DECLSPEC ReturnedValues entryPoint();
DECLSPEC long *Test(int length);
#ifdef __cplusplus
}
#endif
TestPlatform.cpp（控制台应用程序） 我只是想从中调用 Test()
#include "stdafx.h"
#include <Windows.h>
#include <iostream>
#include <conio.h>
#include <strsafe.h>
#define IMPORT
//#define EXPLICIT
using namespace std;
#ifndef EXPLICIT
#include "QSIWrapperUMeLt.h"
//#include "QSIAccessor.h"
#pragma comment(lib, "QSIWrapperUMeLt.lib")
//#pragma comment(lib, "QSIAccessorUMEmpty.lib")
#endif
#ifdef EXPLICIT
typedef long *(*Test)(int length);
HINSTANCE hinstlib;
Test pTest;
#endif
void ErrorExit(LPTSTR lpszFunction);
int _tmain(int argc, _TCHAR* argv[])
{
int temp = 1;
long *data;
#ifdef EXPLICIT
hinstlib = LoadLibrary((LPCWSTR)"QSIWrapperUMeLt.dll");
if(hinstlib)
{
#endif
int i;
cout << "hinstlib was successfully initialized" << endl;
#ifdef EXPLICIT
pTest = (Test)GetProcAddress(hinstlib, (LPCSTR)"Test");
data = pTest(10000);
#else
data = Test(1000);
//callFunction(CameraData *camdata, ReturnedValues *retvals);
#endif
for(i = 0; i < 20; i++)
{
cout << data[i] << endl;
}
#ifdef EXPLICIT
}
else
{
ErrorExit(TEXT("LoadLibrary"));
}
FreeLibrary(hinstlib);
#endif
getch();
return 0;
}
void ErrorExit(LPTSTR lpszFunction)
{
// Retrieve the system error message for the last-error code
LPVOID lpMsgBuf;
LPVOID lpDisplayBuf;
DWORD dw = GetLastError();
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
dw,
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
(LPTSTR) &lpMsgBuf,
0, NULL );
// Display the error message and exit the process
lpDisplayBuf = (LPVOID)LocalAlloc(LMEM_ZEROINIT,
(lstrlen((LPCTSTR)lpMsgBuf) + lstrlen((LPCTSTR)lpszFunction) + 40) * sizeof(TCHAR));
StringCchPrintf((LPTSTR)lpDisplayBuf,
LocalSize(lpDisplayBuf) / sizeof(TCHAR),
TEXT("%s failed with error %d: %s"),
lpszFunction, dw, lpMsgBuf);
MessageBox(NULL, (LPCTSTR)lpDisplayBuf, TEXT("Error"), MB_OK);
LocalFree(lpMsgBuf);
LocalFree(lpDisplayBuf);
ExitProcess(dw);
}
QSIWrapperUMeLt 符号表
C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin>dumpbin /SYMBOLS "C:\Users\...\Desktop\temp version\C_C++libs\QSIWrapperUMeLt\Debug\QSIWrapperUMeLt.li
b"
Microsoft (R) COFF/PE Dumper Version 10.00.30319.01
Copyright (C) Microsoft Corporation. All rights reserved.
Dump of file C:\Users\Deven Bryant\Desktop\temp version\C_C++libs\QSIWrapperUMeLt\Debug\QSIWrapperUMeLt.lib
File Type: LIBRARY
COFF SYMBOL TABLE
000 009C766F ABS notype Static | @comp.id
001 00000000 SECT2 notype External | __IMPORT_DESCRIPTOR_QSIWrapperUMeLt
002 C0000040 SECT2 notype Section | .idata$2
003 00000000 SECT3 notype Static | .idata$6
004 C0000040 UNDEF notype Section | .idata$4
005 C0000040 UNDEF notype Section | .idata$5
006 00000000 UNDEF notype External | __NULL_IMPORT_DESCRIPTOR
007 00000000 UNDEF notype External | ¦QSIWrapperUMeLt_NULL_THUNK_DATA
String Table Size = 0x62 bytes
COFF SYMBOL TABLE
000 009C766F ABS notype Static | @comp.id
001 00000000 SECT2 notype External | __NULL_IMPORT_DESCRIPTOR
String Table Size = 0x1D bytes
COFF SYMBOL TABLE
000 009C766F ABS notype Static | @comp.id
001 00000000 SECT2 notype External | ¦QSIWrapperUMeLt_NULL_THUNK_DATA
String Table Size = 0x25 bytes
Summary
DB .debug$S
14 .idata$2
14 .idata$3
4 .idata$4
4 .idata$5
14 .idata$6
QSIWrapperUMeLt 出口
C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\bin>dumpbin /EXPORTS "C:\Users\...\Desktop\temp version\C_C++libs\QSIWrapperUMeLt\Debug\QSIWrapperUMeLt.dl
l"
Microsoft (R) COFF/PE Dumper Version 10.00.30319.01
Copyright (C) Microsoft Corporation. All rights reserved.
Dump of file C:\Users\Deven Bryant\Desktop\temp version\C_C++libs\QSIWrapperUMeLt\Debug\QSIWrapperUMeLt.dll
File Type: DLL
Section contains the following exports for QSIWrapperUMeLt.dll
00000000 characteristics
500E089F time date stamp Mon Jul 23 19:29:51 2012
0.00 version
1 ordinal base
3 number of functions
3 number of names
ordinal hint RVA name
1 0 00011127 Test = @ILT+290(_Test)
2 1 0001102D entryPoint = @ILT+40(_entryPoint)
3 2 00017580 retvals = _retvals
Summary
1000 .data
1000 .idata
2000 .rdata
1000 .reloc
1000 .rsrc
4000 .text
10000 .textbss