how to call function from dll

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VS2008

Visual-Studio

MFC

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I want to call method in abc.dll written in c++ using vc++ and vs2008.
My code is

C#

/* global handle for the dynamic library */
HMODULE g_hLib = NULL;
#if defined(WIN32)
    #define DERMALOG_LIBNAME "abc.dll"
/* load the library */
   g_hLib = LoadLibrary(DERMALOG_LIBNAME);
   if (g_hLib==NULL)
   {
      printf("%s not found\n", DERMALOG_LIBNAME);

   }
typedef long nRetCode = FC3Initialize(NULL);

METHOD PROTOTYPE IS DrmErrorCode_t DRMAPI FC3Initialize(const char* szReserved);

It is successfully loaded but when I call method it gives linking error...

Error 13 error LNK2019: unresolved external symbol _FC3Initialize@4 referenced in function "public: void __thiscall CZF1SDKLightTutorialDlg::OnBnClickedButton3(void)" (?OnBnClickedButton3@CZF1SDKLightTutorialDlg@@QAEXXZ) ZF1SDKLightTutorialDlg.obj ZF1SDKLightTutorial

Error 14 fatal error LNK1120: 1 unresolved externals C:\Users\Acer\Desktop\a\ZF1SDKDemo_12July2012_imran\ZF1SDKDemo\ZF1SDKDemo\Debug\ZF1SDKDemo.exe 1 ZF1SDKLightTutorial

Posted 12-Jul-12 2:53am

Member 7909353

Updated 12-Jul-12 3:14am

v4

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3 solutions

Solution 1

Take a look at those links here in CP, probably they will help you:

Regular DLL Tutor For Beginners[^]

Step by Step: Calling C++ DLLs from VC++ and VB - Part 1[^]

And this Q&A that seems related to your needs:
using DLL without importing the LIB[^]

Hope this helps...

Posted 12-Jul-12 3:19am

Joan M

Comments

Albert Holguin 12-Jul-12 16:04pm

Those are all good resources... +5

Joan M 12-Jul-12 16:22pm

Thank you Albert!

Solution 2

You cannot make a direct call to a library function unless that library is linked to your program. If you are dynamically loading the DLL at run time then you must use GetProcAddress()[^] and call it through a function pointer.

Posted 12-Jul-12 3:45am

Richard MacCutchan

Comments

Albert Holguin 12-Jul-12 16:03pm

Pretty important step... +5

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Member 7909353 · Accepted Answer · 2012-11-16T02:14:00

Solution 3

make function pointer to function in dll.
And call laoddll function

Posted 16-Nov-12 2:14am

Member 7909353

Comments

Richard MacCutchan 16-Nov-12 8:44am

Which is what I told you four months ago.

Amol Patil May2021 10-May-21 1:12am

Hi,
I am tried to load the DLL in c.DLL loading got successful. I called one dll function, the function called successfully. but inside that dll function one thread got registered after that there was a callback to the platform.there is check of pj_this() and its asserting.how to avoid that assert.looks like pj functions outside of the dll not accessible