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copied!<p><a href="https://stackoverflow.com/questions/20467514/c-char-to-char-conversion#comment30585757_20467514">Jefffrey's comment</a> references the standard, here it is:</p> <blockquote> <p>4.2 Array-to-pointer conversion [conv.array] </p> <p>An lvalue or rvalue of type “array of N T” or “array of unknown bound of T” can be converted to a prvalue of type “pointer to T”. The result is a pointer to the ﬁrst element of the array.</p> </blockquote> <p>And a prvalue is:</p> <blockquote> <p>A prvalue ("pure" rvalue) is an expression that identifies a temporary object (or a subobject thereof) or is a value not associated with any object.</p> </blockquote> <p>You cannot bind a non-const reference to a temporary.</p> <pre><code>int& i = int(); // error char* argv[] = { "", "", nullptr }; // the result of the conversion is a prvalue char**& test = argv; // error </code></pre> <p>Therefore the following code will happily compile:</p> <pre><code>#include <iostream> void f(int& argc, char** const& argv){ std::cout << argv[0] << std::endl; // a } int main() { int argc = 2; char* argv[] = { "a", "b", nullptr }; f(argc, argv); return 0; } </code></pre> <hr /> <p>One important thing I glazed over is pointed out in <a href="https://stackoverflow.com/questions/20467514/c-char-to-char-conversion/20469655?noredirect=1#comment30596711_20469655">Kanze's comment</a>.</p> <p>In the first example provided in the OP, <code>char* argv[]</code> and <code>char** argv</code> are equivalent. Therefore, there is no conversion.</p> <pre><code>std::cout << std::is_array<decltype(argv)>::value << std::endl; // false std::cout << std::is_array<char**>::value << std::endl; // false std::cout << std::is_array<char*[]>::value << std::endl; // true std::cout << std::is_same<decltype(argv), char**>::value << std::endl; // true std::cout << std::is_same<decltype(argv), char*[]>::value << std::endl; // false </code></pre>

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