C++ FAQ Celebrating Twenty-One Years of the C++ FAQ!!!
(Click here for a personal note from Marshall Cline.)
Section 11:
11.1 What's the deal with destructors?
11.2 What's the order that local objects are destructed?
11.3 What's the order that objects in an array are destructed?
11.4 Can I overload the destructor for my class?
11.5 Should I explicitly call a destructor on a local variable?
11.6 Can I call a destructor on a local if I really want to?
11.7 How do I handle the situation from the previous FAQ?
11.8 What if I can't wrap the local in an artificial block?
11.9 Explicitly calling dtor for objects allocated with new?
11.10 What is "placement new" and why would I use it?
11.11 Should a dtor call the dtors for member objects?
11.12 Should a dtor call the dtors for the base class subobject?
11.13 Should my destructor throw an exception when it detects a problem?
11.14 Getting new to allocate memory from a specific memory area?
[11.7] OK, OK already; I won't explicitly call the destructor of a local; but how do I handle the situation from the previous FAQ?

[For context, please read the previous FAQ].

Simply wrap the extent of the lifetime of the local in an artificial block {...}: 

void someCode()
{
  {
    File f;
    ...code that should execute when f is still open...
  }← f's destructor will automagically be called here!

  ...code that should execute after f is closed...
}