This attribute causes the function it is associated with to
be called automatically after
exit() is called.
This attribute is a GNU compiler extension supported by the ARM compiler.
an optional integer value denoting the priority. A destructor with
a high integer value runs before a destructor with a low value.
A destructor with a priority runs before a destructor without a
Priority values up to and including
reserved for internal use. If you use these values, the compiler
gives a warning. Priority values above