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## Macro BOOST_CONTRACT_ASSERT

BOOST_CONTRACT_ASSERT — Preferred way to assert contract conditions.

## Synopsis

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

    BOOST_CONTRACT_ASSERT(cond)

## Description

Any exception thrown from within a contract (preconditions, postconditions, exception guarantees, old value copies at body, class invariants, etc.) is interpreted by this library as a contract failure. Therefore, users can program contract assertions manually throwing an exception when an asserted condition is checked to be `false` (this library will then call the appropriate contract failure handler `boost::contract::precondition_failure`, etc.). However, it is preferred to use this macro because it expands to code that throws `boost::contract::assertion_failure` with the correct assertion file name (using `FILE`), line number (using `LINE`), and asserted condition code so to produce informative error messages (C++11 `func` is not used here because in most cases it will simply expand to the internal compiler name of the lambda function used to program the contract conditions adding no specificity to the error message).

`BOOST_CONTRACT_ASSERT`, `BOOST_CONTRACT_ASSERT_AUDIT`, and `BOOST_CONTRACT_ASSERT_AXIOM` are the three assertion levels predefined by this library.

See Also:

Preconditions, Postconditions, Exceptions Guarantees, Class Invariants, No Macros

Parameters:

`cond` | Boolean contract condition to check. (This is not a variadic macro parameter so any comma it might contain must be protected by round parenthesis and `BOOST_CONTRACT_ASSERT((cond))` will always work.)