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POMSVC++ variadic macro expansion
 

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    <p>So I've got a macro that works nicely in GCC, but not in Microsoft's C++ Compiler. I'm hoping somebody might know of a workaround, or perhaps can explain to me why it behaves this way. </p> <p>I'm sure this macro isn't exactly "standard", but it would really help me out.</p> <p>Here is a functional example of the macro:</p> <pre><code>#define VA_NARGS_IMPL(_1, _2, _3, _4, _5, N, ...) N #define VA_NARGS(...) VA_NARGS_IMPL(__VA_ARGS__, 5, 4, 3, 2, 1) #define FULLY_EXPANDED(count, ...) \ MAC ## count (__VA_ARGS__) #define SEMI_EXPANDED(count, ...) FULLY_EXPANDED(count, __VA_ARGS__) #define EXPAND_THESE(...) SEMI_EXPANDED(VA_NARGS(__VA_ARGS__), __VA_ARGS__) #define ACTUAL_MACRO(x) parent-&gt;GetProperty&lt;x&gt;(); #define MAC1(a) ACTUAL_MACRO(a) #define MAC2(a,b) MAC1(a) ACTUAL_MACRO(b) #define MAC3(a,b,c) MAC2(a,b) ACTUAL_MACRO(c) #define MAC4(a,b,c,d) MAC3(a,b,c) ACTUAL_MACRO(d) #define MAC5(a,b,c,d,e) MAC4(a,b,c,d) ACTUAL_MACRO(e) </code></pre> <p>Here is how I might use this macro:</p> <pre><code>struct MyStructure { void Foo() { EXPAND_THESE(Property1, Property2, Property3, Property4) } Base * parent; } </code></pre> <p>Here's how GCC expands the above:</p> <pre><code>struct MyStructure { void Foo() { parent-&gt;GetProperty&lt;Property1&gt;(); parent-&gt;GetProperty&lt;Property2&gt;(); parent-&gt;GetProperty&lt;Property3&gt;(); parent-&gt;GetProperty&lt;Property4&gt;(); } Base * parent; } </code></pre> <p>But Microsoft for some reason expands all my __VA_ARGS__ as one argument:</p> <pre><code>struct MyStructure { void Foo() { parent-&gt;GetProperty&lt;Property1, Property2, Property3, Property4&gt;(); } Base * parent; } </code></pre> <p>Does anybody know why this is? Is there some trick I can pull to get Microsoft to expand this like GCC? Maybe toss in a couple extra pairs of parentheses?</p> <p>Macros like this could really help me out in replacing a bunch of "glue" code, but because of this problem, I can't move it into my VS project. Any help would be greatly appreciated!</p> <p>Thanks. </p>
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    1. USRobert Kelly
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    1. COIt`s a [bug](http://connect.microsoft.com/VisualStudio/feedback/details/380090/variadic-macro-replacement) and I don`t think they plan on fixing it anytime soon.
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      1. USJesse Good
 

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