Re: [boost] [SCOPE_EXIT] compiler errors for structure members

Subject: Re: [boost] [SCOPE_EXIT] compiler errors for structure members
From: Sid Sacek (ssacek_at_[hidden])
Date: 2009-04-20 11:31:21

>>       struct {
>>             int one;
>>       } test ;
>>       test.one = 55;
>> 
>>       BOOST_SCOPE_EXIT( ( test.one ) )
>>       {
>>       }
>>       BOOST_SCOPE_EXIT_END
>> 
>> The above code gives me lots of compiler errors. Is there a special
>> syntax I have to provide to be able to use structure members?
>> 
>
>This is not supported because only identifiers are allowed. If test was
>a variable of non-local non-anonymous struct type, you could pass it:
>
>BOOST_SCOPE_EXIT( (test ) ) { int one = test.one; ... } BOOST_SCOPE_EXIT_END
>
>Alex

Thank you, Alex. But unfortunately I couldn't use your suggested syntax because the copy-constructor for the structure is being called ( a couple of times. ) Instead, I'm opting for:

        struct ttt {
                int one;
        } test ;

        test.one = 55;
        int *one_ref = &test.one;
        BOOST_SCOPE_EXIT( ( one_ref ) )
        {
                *one_ref = 666; // experimental code
        }
        BOOST_SCOPE_EXIT_END;

This solves my problem. What really surprised me however was that when I made 'one_ref' an int&, the original test.one variable never got modified. Some other ( I assume temp variable ) was modified. If you're wondering what this is about, I'm trying to create a new macro that uses your macro.

Regards,
-Sid Sacek

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