CODEWITHSUNDEEP
c++visual-studiovisual-c++
SortOf
SortOf

Reputation: 469

LINK : fatal error LNK1561: entry point must be defined ERROR IN VC++

I installed MS VS VC++ for the first time in order to start programming OpenGL with GLFW library. I follower instructions on how to install it over at http://shawndeprey.blogspot.com/2012/02/setting-up-glfw-in-visual-studio-2010.html Then I wrote this simple program, just to test it, which did work on Eclipse:

#include <stdlib.h>
#include <GL/glfw.h>

using namespace std;

int main()
{
    int running = GL_TRUE;
    if (!glfwInit()) {
        exit(EXIT_FAILURE);
    }

    if (!glfwOpenWindow(300, 300, 0, 0, 0, 0, 0, 0, GLFW_WINDOW)) {
        glfwTerminate();
        exit(EXIT_FAILURE);
    }

    while (running) {
        // glClear( GL_COLOR_BUFFER_BIT );
        glfwSwapBuffers();
        running = !glfwGetKey(GLFW_KEY_ESC) && glfwGetWindowParam(GLFW_OPENED);
    }

    glfwTerminate();
    exit(EXIT_SUCCESS);
    return 0;
}

But then I got this awful error:

------ Build started: Project: first1, Configuration: Debug Win32 ------
   LINK : fatal error LNK1561: entry point must be defined
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

I know, I've looked around on the internet and the only solution I found was "It requires main() function in order to work". I obviously have it, right there, but it still throws me the same fatal error :(

Would be great to get response on how to fix it. There might me a flaw in the installation process or something.

Upvotes: 44

Views: 216305

Answers (8)

Michelangelo Machado
Michelangelo Machado

Reputation: 149

In my case, the program was running fine, but after one day, I just ran into this problem without doing anything...

The solution was to manually add 'Main' as the Entry Point (before editing, the area was empty):

enter image description here

Upvotes: 12

woodpecker
woodpecker

Reputation: 211

Main was missing in the entry point configuration. enter image description here

Upvotes: 0

Michael Haephrati
Michael Haephrati

Reputation: 4215

You can get this error if you define a project as an .exe but intent to create a .lib or a .dll

Upvotes: 7

Brackets
Brackets

Reputation: 572

In Visual Studio: Properties -> Advanced -> Entry Point -> write just the name of the function you want the program to begin running from, case sensitive, without any brackets and command line arguments.

Upvotes: 0

sdff
sdff

Reputation: 11

I've had this happen on VS after I changed the file's line endings. Changing them back to Windows CR LF fixed the issue.

Upvotes: 1

collaborator
collaborator

Reputation: 632

Is this a console program project or a Windows project? I'm asking because for a Win32 and similar project, the entry point is WinMain().

  1. Right-click the Project (not the Solution) on the left side.
  2. Then click Properties -> Configuration Properties -> Linker -> System

If it says Subsystem Windows your entry point should be WinMain(), i.e. 

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPWSTR lpCmdLine, int nShowCmd)
{
   your code here ...
}

Besides, speaking of the comments. This is a compile (or more precisely a Link) error, not a run-time error. When you start to debug, the compiler needs to make a complete program (not just to compile your module) and that is when the error occurs.

It does not even get to the point being loaded and run.

Upvotes: 29

Matas Lesinskas
Matas Lesinskas

Reputation: 444

change it to Console (/SUBSYSTEM:CONSOLE) it will work

Upvotes: 8

ash
ash

Reputation: 3474

It cant find the entry point for your program, in this case main(). Your linker settings are likely incorrect.

See this post here

Upvotes: 8

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