Function template condition

Function template condition_if

boost::contract::condition_if — Select compilation and execution of a boolean functor template condition using a nullary boolean meta-function (not needed on C++17 compilers, use if constexpr instead).

Synopsis

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


template<typename Pred, typename Then> 
  bool condition_if(Then f, bool else_ = true);

Description

This is equivalent to boost::contract::condition_if_c<Pred::value>(f, else_). Compile and execute the nullary boolean functor template call f() if and only if the specified nullary boolean meta-function Pred::value is true, otherwise trivially return else_ (true by default) at run-time.

See Also: Assertion Requirements

Parameters:

`f`	Nullary boolean functor template. The functor template call `f()` is compiled and executed if and only if `Pred::value` is `true`.
`else_`	Boolean value to return when `Pred::value` is `false` (instead of compiling and executing the functor template call `f()`).

Template Parameters:

Pred

Nullary boolean meta-function selecting when the functor template call f() should be compiled and executed.

Returns:

Boolean value returned by f() if the static predicate Pred::value is true. Otherwise, trivially return else_.

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