id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
5818	Compile error with BOOST_REQUIRE_THROW	martin.desharnais@…	Gennadiy Rozental	"I recently post this email on the boost-users mailing list:

Hi,
I've just found that we have a compiler error when using the BOOST_REQUIRE_THROW macro in a if/else statement with implicit block. Let's have an example:

BOOST_AUTO_TEST_CASE(foo)
{
    if(true)
        BOOST_REQUIRE_THROW(throw std::exception(), std::exception);
    else
        BOOST_REQUIRE_THROW(throw std::exception(), std::exception);
}

Will fail with:

file.cpp: In member function ‘void foo::test_method()’:
file.cpp:184:2: error: ‘else’ without a previous ‘if’

To make it work, we need to put explicit block:


BOOST_AUTO_TEST_CASE(foo)
{
    if(true)
    {
        BOOST_REQUIRE_THROW(throw std::exception(), std::exception);
    }
    else
    {
        BOOST_REQUIRE_THROW(throw std::exception(), std::exception);
    }
}

Wouldn't it be possible to add this block in the macro so library users don't have to care about?

And got this answer:

BOOST_REQUIRE_THROW expands into a try { ... } catch { ... } block.
Such a block is a valid single statement, but if you put a ; at the
end of the catch block, that semicolon terminates the if statement.
[...]
The macro could be enclosed in a do { .... } while (0) construct in
order to make it syntactically appear more like a single statement
that is terminated with a semicolon."	Feature Requests	closed	To Be Determined	test	Boost 1.47.0	Cosmetic	fixed	BOOST_REQUIRE_THROW