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Determining Type Completeness with a Custom Template
Incomplete types, while not fully defined, play a crucial role in C programming. However, determining whether a type is complete can be challenging, especially with the lack of a dedicated template like Boost's is_complete.
Proposed Solution
Although a universal solution that fully adheres to the One Definition Rule (ODR) may be elusive, a platform-specific approach has proven effective for Microsoft Visual C . As outlined by Alexey Malistov, the following template can be employed:
<code class="cpp">namespace { template<class T, int discriminator> struct is_complete { static T & getT(); static char (& pass(T))[2]; static char pass(...); static const bool value = sizeof(pass(getT()))==2; }; }</code>
Usage
To leverage this template, simply utilize the macro IS_COMPLETE(X), where X is the type in question. For instance:
<code class="cpp">#define IS_COMPLETE(X) is_complete<X,__COUNTER__>::value</code>
Caveat
It's crucial to note that the __COUNTER__ macro is not part of the C standard. Therefore, this solution may not be suitable for all compilers.
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