What is the function try block handler?

Question

I came across this question recently - What is function try block handler?

Also, where would it be useful?

Answer 1

Here you can find a good explanation.

It could be useful in an initialization list of a constructor:

struct A
{
private:
  std::string s;
public:
  A( int value ) try : s( boost::lexical_cast<std::string>( value ) ) {}
  catch ( boost::bad_lexical_cast ) { /* handle lexical_cast exception here */ }
};

Answer 2

a function written like this:

void fun ()
try 
{
.....
.....
}
catch(SomeException & e)
{
....
....
}

is called a function try block.

This is typically used with constructors with initialization lists to catch the exception thrown during the construction of an object constructed in the initialization list.