Solving the “LNK1561 Entry Point Must Be Defined

The “LNK1561 Entry Point Must Be Defined” is an error that can occur when linking C/C++ static libraries. This error is caused by linking an object file containing a class without a symbol that can serve as the entry point for the program. In this guide, we will discuss the basic causes of the error and show you how to solve it.

Causes of the Error

The “LNK1561 Entry Point Must Be Defined” error occurs when attempting to link the static library to a program, but the static library does not include an entry point. This error is commonly caused by one of the following reasons:

• You have not included a main()func tion in your code and attempted to link it.
• You have included a main()function in your code but it contains a syntax error or other error.
• You are trying to link a class without defining a main()function in the code.

Solving the Error

The solution to the “LNK1561 Entry Point Must Be Defined” error depends on the cause of the error. Let's take a look at each of the common causes of this error and discuss the solutions.

1. No Main Function

If you are trying to link a program without a main()function, the solution is to add a main()function. This is the entry point of your program, and it must be defined in order to be able to link it.

2. Invalid Main Function

If you are trying to link a program with a main()function, but the function contains a syntax error or you get an error otherwise, the solution is to fix the syntax error or other error.

3. Class Without Main Function

If you are trying to link a class without a main()function, the solution is to define an entry point for the class. This entry point can be called from the main function or you can define an explicit entry point for the class.

FAQ

Q1: What is the "LNK1561 Entry Point Must Be Defined" Error?

A1: The “LNK1561 Entry Point Must Be Defined” error is an error that occurs when linking C/C++ static libraries. This error is caused by linking an object file containing a class without a symbol that can serve as the entry point for the program.

Q2: What causes the "LNK1561 Entry Point Must Be Defined" Error?

A2: The “LNK1561 Entry Point Must Be Defined” error is commonly caused by one of three reasons: you have not included a main()function in your code and attempted to link it, you have included a main()function in your code but it contains a syntax error or other error, or you are trying to link a class without defining a main()function in the code.

Q3: How do I solve the "LNK1561 Entry Point Must Be Defined" Error?

A3: The solution to this error depends on the cause of the error. If you have not included a main()function in your program, you must add one. If your main()function contains a syntax or other error, you must fix it. If you are trying to link a class without a main()function, you must define an entry point.

Q4: How do I define an entry point for a class?

A4: You can define an entry point for a class by either calling it from the main()function or by defining an explicit entry point for the class.

Q5: Where can I find more information about the “LNK1561 Entry Point Must Be Defined” Error?

A5: You can find more information about this error on MSDN and Stack Overflow.