The brackets before the obviously called expression must have (pointer) function type compiler error C2064, compiler c2064

The brackets before the obviously called expression must have (pointer) function type compiler error C2064, compiler c2064

When I saw the phrase "the parentheses before the obviously called expression must have (pointer) function type", I found that my language level is poor and I cannot understand it at all, it took only half a day to know what went wrong.

A simple example

Class CTest {void (CTest: * m_pFun) (); void CallFun () {(this-> * m_pFun) (); // OK, the object pointer and function name must be enclosed in parentheses. The * sign (this-> * m_pFun () must be added before the function name; // error (this-> m_pFun )(); // error} // link to this article: http://www.cnblogs.com/vcpp123/p/5902839.html };

 

For more information, see MSDN. Link: https://msdn.microsoft.com/query/dev14.query? AppId = Dev14IDEF1 & l = ZH-CN & k = k (C2064) & rd = true

Compiler error C2064

Term does not evaluate to a function taking N arguments

A call is made to a function through an expression. The expression does not evaluate to a pointer to a function that takes the specified number of arguments.

In this example, the code attempts to call non-functions as funwing. The following sample generates C2064:

// C2064.cppint i, j;char* p;void func() {j = i();    // C2064, i is not a functionp();        // C2064, p doesn't point to a function}

You must call pointers to non-static member functions from the context of an object instance. The following sample generates C2064, and shows how to fix it:

// C2064b.cppstruct C {void func1() {}void func2() {}};typedef void (C::*pFunc)();int main() {C c;pFunc funcArray[2] = { &C::func1, &C::func2 };(funcArray[0])();    // C2064 (c.*funcArray[0])(); // OK - function called in instance context}

Within a class, member function pointers must also indicate the calling object context. The following sample generates C2064 and shows how to fix it:

// C2064d.cpp// Compile by using: cl /c /W4 C2064d.cppstruct C {typedef void (C::*pFunc)();pFunc funcArray[2];void func1() {}void func2() {}C() {funcArray[0] = &C::func1;funcArray[1] = &C::func2;}void func3() {(funcArray[0])();   // C2064(this->*funcArray[0])(); // OK - called in this instance context}};