Function make_old

boost::contract::make_old — Make an old value pointer (but not for virtual public functions and public functions overrides).

Synopsis

// In header: <boost/contract/old.hpp>


old_pointer make_old(old_value const & old);

Description

The related old value pointer will not be null if the specified old value was actually copied. This function is often only used by code expanded by BOOST_CONTRACT_OLDOF(old_expr):

boost::contract::make_old(boost::contract::copy_old() ? old_expr :
        boost::contract::null_old())

See Also:

No Macros

Parameters:

old

Old value which is usually implicitly constructed from the user old value expression to be copied (use the ternary operator ?: to avoid evaluating the old value expression all together when boost::contract::copy_old() is false).

Returns:

Old value pointer (usually implicitly converted to either boost::contract::old_ptr or boost::contract::old_ptr_if_copyable in user code).

Boost C++ Libraries