assignment of function

What does that mean?????

Depends on the context.

Yes you can assign a function pointer value into a suitably typed variable. Perhaps you are asking what
is the syntax for the type of such a variable?

If you mean function pointer / variables, then you can do code like this:

//typedef = type definition
//void = return value, void = none
//FunctionTypeName = the name of the type
//int = arguments
typedef void (*FunctionTypeName)(int);

void aFunction(int value)
  //value is 123;

void CallFunction(FunctionTypeName theFunction)


If you mean assign a return value you can do this:

int getTheValue()
  return 123; //Return a value

int theValue = getTheValue();
//theValue is now 123

If it is in an error message then it probably means you forgot the () on a function call.

youcefaek: you would do well to read How To Ask Questions The Smart Way.