Emilio Cobos Álvarez
b2e224354b
Using operator= is not quite sound in presence of destructors and operator overloading. It's perfectly fine to assume that the left-hand-side of an operator= expression is valid memory, however we're using uninitialized memory here, that may not be the case. Use placement new to properly construct tagged unions. I don't need this with any urgency, but it's the right thing to do in presence of complex types, and the current code seems a bomb waiting to explode :)
39 lines
497 B
C++
39 lines
497 B
C++
#include <cstdarg>
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#include <cstdint>
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#include <cstdlib>
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#include <new>
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struct Foo {
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enum class Tag {
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A,
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};
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struct A_Body {
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float _0[20];
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};
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Tag tag;
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union {
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A_Body a;
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};
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static Foo A(const float (&a0)[20]) {
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Foo result;
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for (int i = 0; i < 20; i++) {
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::new (&result.a._0[i]) (float)(a0[i]);
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}
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result.tag = Tag::A;
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return result;
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}
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bool IsA() const {
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return tag == Tag::A;
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}
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};
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extern "C" {
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void root(Foo a);
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} // extern "C"
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