Microsoft KB Archive Search

Notice: This website is an unofficial Microsoft Knowledge Base (hereinafter KB) archive and is intended to provide a reliable access to deleted content from Microsoft KB. All KB articles are owned by Microsoft Corporation. Read full disclaimer for more details.

  1. Home
  2. You receive an LNK4197 error in the 64-bit version of the Visual C++ Compiler

You receive an LNK4197 error in the 64-bit version of the Visual C++ Compiler

View products that this article applies to.

Summary

When you build a DLL by using the 64-bit version of the Microsoft Visual C++ Compiler and Linker, you may receive Linker error number LNK4197 if a function has been declared for export more than one time.

↑ Back to the top

Symptoms

The Linker output may be similar to the following:
C:\>link /NOLOGO /def:Sample.def /pdb:Sample.pdb /out:Sample.dll  Sample.obj
Sample.obj : warning LNK4197: export 'DllSample' specified multiple times; using first specification
   Creating library Sample.lib and object Sample.exp

↑ Back to the top

Cause

The Linker error number LNK4197 is generated when a function has been declared for export more than one time. A function is declared for export in one of the following ways:
  • The function is declared by using the __declspec(dllexport) keyword in your C source file:
    __declspec(dllexport) int DllSample() 
    {
       return 42;
    }
  • The function is declared by using a module-definition (.DEF) file:
    EXPORTS
       DllSample
This Linker error may occur most frequently when both the __declspec(dllexport) keyword and a .DEF file are used to define the same function name in a .DLL project.

↑ Back to the top

Resolution

To resolve this behavior, define exported functions only one time, either by using the __declspec(dllexport) keyword or by using a .DEF file. Do not use both of these methods.

↑ Back to the top

Status

This behavior is by design.

↑ Back to the top

More Information

Declaring a function for export more than one time may not produce the Linker error that is described in the "Symptoms" section of this article in 32-bit versions of the Microsoft Windows C++ Compiler and Linker. However, Microsoft recommends that you define function exports only one time in both 32-bit and 64-bit versions of the Windows C++ Compiler and Linker.

↑ Back to the top

Keywords: kbddk, kbprb, kb

↑ Back to the top

Article Info
Article ID : 835326
Revision : 4
Created on : 8/1/2019
Published on : 8/1/2019
Exists online : False
Views : 226