2 <clause number="17.5.1.3" title="Output parameters">
3 <paragraph>A parameter declared with an out modifier is an output parameter. Similar to a reference parameter, an output parameter does not create a new storage location. Instead, an output parameter represents the same storage location as the variable given as the argument in the method invocation. </paragraph>
4 <paragraph>When a formal parameter is an output parameter, the corresponding argument in a method invocation must consist of the keyword out followed by a <non_terminal where="12.4">variable-reference</non_terminal> (<hyperlink>12.3.3</hyperlink>) of the same type as the formal parameter. A variable need not be definitely assigned before it can be passed as an output parameter, but following an invocation where a variable was passed as an output parameter, the variable is considered definitely assigned. </paragraph>
5 <paragraph>Within a method, just like a local variable, an output parameter is initially considered unassigned and must be definitely assigned before its value is used. </paragraph>
6 <paragraph>Every output parameter of a method must be definitely assigned before the method returns. </paragraph>
7 <paragraph>Output parameters are typically used in methods that produce multiple return values. <example>[Example: For example: <code_example><![CDATA[
11 static void SplitPath(string path, out string dir, out string name) {
14 char ch = path[i - 1];
15 if (ch == '\\' || ch == '/' || ch == ':') break;
18 dir = path.Substring(0, i);
19 name = path.Substring(i);
23 SplitPath("c:\\Windows\\System\\hello.txt", out dir, out name);
24 Console.WriteLine(dir);
25 Console.WriteLine(name);
28 ]]></code_example></example></paragraph>
30 <example>The example produces the output: <code_example><![CDATA[
33 ]]></code_example></example>
36 <example>Note that the dir and name variables can be unassigned before they are passed to SplitPath, and that they are considered definitely assigned following the call. end example]</example>