PRB: Missing /c Compiler Option Causes LNK1561 Linker Error (228455)

The information in this article applies to:

Microsoft Visual C++, 32-bit Enterprise Edition 6.0
Microsoft Visual C++, 32-bit Professional Edition 6.0
Microsoft Visual C++, 32-bit Learning Edition 6.0

This article was previously published under Q228455

SYMPTOMS

When compiling a multiple source file project that creates a pre-compiled header file inside the Visual C++ Integrated Development Environment (IDE), the following error can occur:

Compiling...
StdAfx.cpp
LINK : fatal error LNK1561: entry point must be defined
Error executing cl.exe.

NOTE: The linker error is generated during the compiler phase of the build.

CAUSE

The /c compiler option is missing from the build settings.

RESOLUTION

Add /c to the compiler options. To do this, you must edit the compiler options in the Project Options box in the C/C++ tab under Project Settings.

NOTE: This box is only editable if the whole project is selected in the tree control on the Project Settings.

STATUS

This behavior is by design.

MORE INFORMATION

By default, the Visual C/C++ compiler attempts to compile and link in a single step. The /c (Compile without Linking) option is used to tell the compiler to compile only. Since Visual C++ compiles and links in separate steps, then /c is required for all Visual C++ builds.

To reproduce the error, create a default MFC project and remove the /c option from the Project Settings by editing the compiler options in the Project Options box in the C/C++ tab under Project Settings.

REFERENCES

Modification Type:	Major	Last Reviewed:	11/18/2003
Keywords:	kbCompiler kbprb KB228455