KB167748 - PRB: Variable Scope in for-statement Extends Beyond Loop

Article ID: 167748

Article Last Modified on 7/5/2005

APPLIES TO

Microsoft Visual C++ 5.0 Standard Edition
Microsoft Visual C++ 6.0 Service Pack 5

This article was previously published under Q167748

SYMPTOMS

If you declare the same variable in two different for-statements, the following error may appear:

Test.cpp(4) : error C2374: 'i' : redefinition; multiple initialization

CAUSE

The scope of a variable declared in the initialization part of a "for" loop is given local scope, as if it had been declared immediately prior to the for-statement.

RESOLUTION

Compile with /Za, Disable Language Extensions. To select this option in Developer Studio, select Project, Settings, and then click the C/C++ Tab. Change the Category to Customize and select Disable Language Extensions.

If you cannot use the /Za option, you can work around the problem by #defining the "for" keyword as follows:

#define for if(0);else for

MORE INFORMATION

/* Compile Options Needed to compile without error: /Za */ 

 /* test.cpp */ 
 void main()  {
for (int i=0; i<10; i++)
   ;
for (int i=0; i<15; i++)
   ;
 }

Keywords: kblangcpp kbprb KB167748