Not able to call the function from C DLL - c++

Question

//DLL Code
#include <stdio.h>
extern "C"
{
__declspec(dllexport) void DisplayHelloFromDLL()
{
printf("Hello from DLL !\n");
}
}
//Program Accessing DLL
#include<windows.h>
#include<iostream>
#include<conio.h>
typedef void (*DisplayHelloFromDLLFuncPtr)();
using namespace std;
int main()
{
HINSTANCE hGetProcIDDLL = LoadLibrary("L:\\C_Learning\\Library\\MyLib\\Debug\\MyLib.dll");
if (!hGetProcIDDLL)
{
cout << "\nCould Not The Library";
return EXIT_FAILURE;
}
else
{
cout << "\nDLL is Loaded";
}
DisplayHelloFromDLLFuncPtr LibMainEntryPoint=(DisplayHelloFromDLLFuncPtr)GetProcAddress(hGetProcIDDLL, "DisplayHelloFromDLL");
if (!DisplayHelloFromDLL)
{
cout << "\nCould not locate the function";
return EXIT_FAILURE;
}
cout << DisplayHelloFromDLL();
return EXIT_SUCCESS;
_getch();
return 0;
}
Code executes till cout statement in else condition.
Receive Error while compiling for Function in DLL.
Error received 'DisplayHelloFromDLL': undeclared identifier
Ran Depends.exe which confirms about the function availability in DLL address space.
DLL and Sample Program is compiled with 32-bit environment.
6.Program sole purpose is to call function C DLL and print Hello From DLL message.
Any Suggestions ?

Answer 1

You named the variable holding the "DisplayHelloFromDLL" function pointer as "LibMainEntryPoint":
DisplayHelloFromDLLFuncPtr LibMainEntryPoint=(DisplayHelloFromDLLFuncPtr)GetProcAddress(hGetProcIDDLL, "DisplayHelloFromDLL");
but then you try to use it with different name (DisplayHelloFromDLL):
if (!DisplayHelloFromDLL) ...
Be consistent with the variable names, and the code should work.
change it to:
DisplayHelloFromDLLFuncPtr DisplayHelloFromDLL=(DisplayHelloFromDLLFuncPtr)GetProcAddress(hGetProcIDDLL, "DisplayHelloFromDLL");