...one of the most highly
regarded and expertly designed C++ library projects in the
world.
— Herb Sutter and Andrei
Alexandrescu, C++
Coding Standards
BOOST_CONTRACT_FUNCTION — Program contracts that can be completely disabled at compile-time for (non-public) functions.
// In header: <boost/contract_macro.hpp>
BOOST_CONTRACT_FUNCTION()
This is used together with BOOST_CONTRACT_PRECONDITION
, BOOST_CONTRACT_POSTCONDITION
, BOOST_CONTRACT_EXCEPT
, and BOOST_CONTRACT_OLD
to specify preconditions, postconditions, exception guarantees, and old value copies at body that can be completely disabled at compile-time for (non-public) functions:
void f(...) { BOOST_CONTRACT_OLD_PTR(old_type)(old_var); BOOST_CONTRACT_FUNCTION() BOOST_CONTRACT_PRECONDITION([&] { // Optional. BOOST_CONTRACT_ASSERT(...); ... }) BOOST_CONTRACT_OLD([&] { // Optional. old_var = BOOST_CONTRACT_OLDOF(old_expr); ... }) BOOST_CONTRACT_POSTCONDITION([&] { // Optional. BOOST_CONTRACT_ASSERT(...); ... }) BOOST_CONTRACT_EXCEPT([&] { // Optional. BOOST_CONTRACT_ASSERT(...); ... }) ; ... // Function body. }
This can be used to program contracts for non-member functions but also for private and protected functions, lambda functions, loops, arbitrary blocks of code, etc. For optimization, this can be omitted for code that does not have preconditions, postconditions, and exception guarantees.
BOOST_CONTRACT_FUNCTION()
expands to code equivalent to the following (note that no code is generated when BOOST_CONTRACT_NO_FUNCTIONS
is defined):
#ifndef BOOST_CONTRACT_NO_FUNCTIONS boost::contract::check internal_var = boost::contract::function() #endif
Where:
internal_var
is a variable name internally generated by this library (this name is unique but only on different line numbers so this macro cannot be expanded multiple times on the same line).
See Also:
Disable Contract Compilation, Non-Member Functions, Private and Protected Functions, Lambdas, Loops, Code Blocks