////
Copyright 2019 Peter Dimov
Distributed under the Boost Software License, Version 1.0.
http://www.boost.org/LICENSE_1_0.txt
////

[#reference]
# Reference
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[#synopsis]
## <boost/throw_exception.hpp> Synopsis

```
#include <boost/assert/source_location.hpp>
#include <boost/config.hpp>
#include <exception>

namespace boost
{

#if defined( BOOST_NO_EXCEPTIONS )

BOOST_NORETURN void throw_exception( std::exception const & e ); // user defined

BOOST_NORETURN void throw_exception( std::exception const & e,
  boost::source_location const & loc ); // user defined

#else

template<class E> BOOST_NORETURN void throw_exception( E const & e );

template<class E> BOOST_NORETURN void throw_exception( E const & e,
  boost::source_location const & loc );

#endif

} // namespace boost

#define BOOST_THROW_EXCEPTION(x) \
  ::boost::throw_exception(x, BOOST_CURRENT_LOCATION)

namespace boost
{

template<class E> BOOST_NORETURN void throw_with_location( E && e,
  boost::source_location const & loc = BOOST_CURRENT_LOCATION );

template<class E> boost::source_location get_throw_location( E const & e );

} // namespace boost
```

## throw_exception

```
#if defined( BOOST_NO_EXCEPTIONS )

BOOST_NORETURN void throw_exception( std::exception const & e ); // user defined

#else

template<class E> BOOST_NORETURN void throw_exception( E const & e );

#endif
```

Requires: :: `E` must have `std::exception` as a public and unambiguous base
  class.

Effects: ::
  * When exceptions aren't available, the function is declared, but
    not defined. The user is expected to supply an appropriate definition.
  * Otherwise, if `BOOST_EXCEPTION_DISABLE` is defined, the function
    throws `e`.
  * Otherwise, the function throws an object of a type derived from `E`,
    derived from `boost::exception`, if `E` doesn't already derive from
    it, and containing the necessary support for `boost::exception_ptr`.

```
#if defined( BOOST_NO_EXCEPTIONS )

BOOST_NORETURN void throw_exception( std::exception const & e,
  boost::source_location const & loc ); // user defined

#else

template<class E> BOOST_NORETURN void throw_exception( E const & e,
  boost::source_location const & loc );

#endif
```

Requires: :: `E` must have `std::exception` as a public and unambiguous base
  class.

Effects: ::
  * When exceptions aren't available, the function is declared, but
    not defined. The user is expected to supply an appropriate definition.
  * Otherwise, if `BOOST_EXCEPTION_DISABLE` is defined, the function
    throws `e`.
  * Otherwise, the function throws an object of a type derived from `E`,
    derived from `boost::exception`, if `E` doesn't already derive from
    it, and containing the necessary support for `boost::exception_ptr`. The
    `boost::exception` base class is initialized to contain the source
    location `loc`.

## throw_with_location

```
template<class E> BOOST_NORETURN void throw_with_location( E && e,
  boost::source_location const & loc = BOOST_CURRENT_LOCATION );
```

Requires: :: `std::decay<E>::type` must have `std::exception` as a public
  and unambiguous base class.

Effects: ::
  * When exceptions aren't available, `boost::throw_exception( e, loc );`
  * Otherwise, the function throws an object of a type derived from `E`,
    such that, if this object `x` is caught as `std::exception` or `E`,
    `boost::get_throw_location( x )` would return `loc`.

## get_throw_location

```
template<class E> boost::source_location get_throw_location( E const & e );
```

Requires: :: `E` must be polymorphic.
Effects: ::
* If `e` is a subobject of the object thrown by `boost::throw_with_location( x, loc )`, returns `loc`.
* If `dynamic_cast<boost::exception const*>( e )` returns a nonzero value, returns the source location stored in that `boost::exception` subobject, if any.
* Otherwise, returns a default constructed source location.