Fixing 'lnk1561: Entry Point Must Be Defined' Link Fatal Error

Are you a programmer getting a lnk1561: Entry Point Must Be Defined link fatal error when trying to link an object file and executable file? If so, then this guide is for you!

Problem Overview

The lnk1561: Entry Point Must Be Defined error indicates that the linker has not been able to find an entry point for the linker to begin running the program. This commonly occurs when the entry point has not been defined or when the object file that contains the definition is not being linked as part of the project.

Step by Step Solution

  1. Open the object file containing the entry point definition. In most cases, the definition will be in the form of a main entry point.
  2. Search the object files for the entry point definition. If you are unable to locate the definition in one or more of the object files, you will need to add the source file which contains the definition to the project.
  3. Once you have located or added the source file, ensure that all of the necessary files are being linked in the project settings. You may also need to ensure that you are using the correct compiler setting to ensure that the definition can be found.
  4. Rebuild the project and the lnk1561: Entry Point Must Be Defined error should disappear.


Q: How can I prevent this error from occurring in the future?

A: To prevent this error from occurring, ensure that all of the necessary files are linked into the project and check to make sure the entry point definition is being included in the project. Additionally, make sure that the compiler settings being used are correct.

Q: Is this error specific to a certain compiler?

A: No, this error can occur regardless of the compiler you are using.


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