Why Am I Getting the 'Error LNK2019 unresolved external symbol _main' in my Windows Program?

Error: Unresolved External Symbol "_main"

Problem Description

You encounter the following error when compiling a Windows program:

Error LNK2019 unresolved external symbol _main referenced in function "int __cdecl invoke_main(void)" (?invoke_main@@YAHXZ)

Explanation

This error indicates that the linker cannot find the _main function, which is the entry point for a Windows program. This can occur when the linker is not able to link against the correct library or module that defines _main.

Solution

To resolve this error, check the following:

1. SubSystem Setting:

Open the project properties and ensure that the following settings are correct:

• Configuration Properties → Linker → System → SubSystem: Set to Windows.

2. Linker Options:

Verify the linker options in Configuration Properties → Linker → General:

• Additional Library Directories: Include any necessary directories where required libraries reside.
• Additional Dependencies: Link against the appropriate libraries, typically kernel32.lib.

Sample Code with Main Function

For clarity, here is a sample code that includes a main function:

int main() {
  // Your code goes here
  return 0;
}

Additional Notes

• Visual Studio projects usually link against the **_mainCRTStartup function in the **msvcrt dynamic-link library (DLL).
• If you are using a non-Visual Studio compiler, you may need to specify the _main function explicitly.
• Ensure that your project's source code contains a valid main function definition.
• If the problem persists, consider rebuilding the project or cleaning the solution and rebuilding.

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