/Zc:forScope (Force Conformance in for Loop Scope)
Used to implement standard C++ behavior for for loops with Microsoft extensions (/Ze).
Syntax
/Zc:forScope[-]
Remarks
Standard behavior is to let a for loop's initializer go out of scope after the for loop. Under /Zc:forScope- and /Ze, the for loop's initializer remains in scope until the local scope ends.
The /Zc:forScope option is on by default. /Zc:forScope is not affected when the /permissive- option is specified.
The /Zc:forScope- option is deprecated and will be removed in a future release. Use of /Zc:forScope- generates deprecation warning D9035.
The following code compiles under /Ze but not under /Za:
// zc_forScope.cpp
// compile by using: cl /Zc:forScope- /Za zc_forScope.cpp
// C2065, D9035 expected
int main() {
// Compile by using cl /Zc:forScope- zc_forScope.cpp
// to compile this non-standard code as-is.
// Uncomment the following line to resolve C2065 for /Za.
// int i;
for (int i = 0; i < 1; i++)
;
i = 20; // i has already gone out of scope under /Za
}
If you use /Zc:forScope-, warning C4288 (off by default) is generated if a variable is in scope because of a declaration that was made in a previous scope. To demonstrate this, remove the // characters in the example code to declare int i.
You can modify the run-time behavior of /Zc:forScope by using the conform pragma.
If you use /Zc:forScope- in a project that has an existing .pch file, a warning is generated, /Zc:forScope- is ignored, and compilation continues by using the existing .pch files. If you want a new .pch file generated, use /Yc (Create Precompiled Header File).
For more information about conformance issues in Visual C++, see Nonstandard Behavior.
To set this compiler option in the Visual Studio development environment
Open the project's Property Pages dialog box. For details, see Set C++ compiler and build properties in Visual Studio.
Select the Configuration Properties > C/C++ > Language property page.
Modify the Force Conformance in For Loop Scope property.