Compiler Error C2712

cannot use __try in functions that require object unwinding

Remarks

Error C2712 can occur if you use /EHsc, and a function with structured exception handling also has objects that require unwinding (destruction).

Possible solutions:

• Move code that requires SEH to another function

• Rewrite functions that use SEH to avoid the use of local variables and parameters that have destructors. Do not use SEH in constructors or destructors

• Compile without /EHsc

Error C2712 can also occur if you call a method declared by using the __event keyword. Because the event might be used in a multithreaded environment, the compiler generates code that prevents manipulation of the underlying event object, and then encloses the generated code in an SEH try-finally statement. Consequently, error C2712 will occur if you call the event method and pass by value an argument whose type has a destructor. One solution in this case is to pass the argument as a constant reference.

C2712 can also occur if you compile with /clr:pure and declare a static array of pointers-to-functions in a __try block. A static member requires the compiler to use dynamic initialization under /clr:pure, which implies C++ exception handling. However, C++ exception handling is not allowed in a __try block.

The /clr:pure and /clr:safe compiler options are deprecated in Visual Studio 2015 and unsupported in Visual Studio 2017.

Example

The following sample generates C2712 and shows how to fix it.

// C2712.cpp
// compile with: /clr:pure /c
struct S1 {
   static int smf();
   void fnc();
};

void S1::fnc() {
   __try {
      static int (*array_1[])() = {smf,};   // C2712

      // OK
      static int (*array_2[2])();
      array_2[0] = smf;
    }
    __except(0) {}
}