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| -rw-r--r-- | doc/go_programming_faq.html | 38 |
1 files changed, 37 insertions, 1 deletions
diff --git a/doc/go_programming_faq.html b/doc/go_programming_faq.html index ecb64983c..3c4f0e1ba 100644 --- a/doc/go_programming_faq.html +++ b/doc/go_programming_faq.html @@ -125,7 +125,43 @@ should recognise such cases and optimize its use of OS threads. For now, </p> -<h2 id="Closures">Closures</h2> +<h2 id="Functions_methods">Functions and Methods</h2> + +<h3 id="different_method_sets"> +Why do T and *T have different method sets?</h3> + +<p> +From the <a href="http://golang.org/doc/go_spec.html#Types">Go Spec</a>: +</p> + +<blockquote> +The method set of any other named type <code>T</code> consists of all methods +with receiver type <code>T</code>. The method set of the corresponding pointer +type <code>*T</code> is the set of all methods with receiver <code>*T</code> or +<code>T</code> (that is, it also contains the method set of <code>T</code>). +</blockquote> + +<p> +If an interface value contains a pointer <code>*T</code>, +a method call can obtain a value by dereferencing the pointer, +but if an interface value contains a value <code>T</code>, +there is no useful way for a method call to obtain a pointer. +</p> + +<p> +If not for this restriction, this code: +</p> + +<pre> +var buf bytes.Buffer +io.Copy(buf, os.Stdin) +</pre> + +<p> +would copy standard input into a <i>copy</i> of <code>buf</code>, +not into <code>buf</code> itself. +This is almost never the desired behavior. +</p> <h3 id="closures_and_goroutines"> Why am I confused by the way my closures behave as goroutines?</h3> |