<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <!-- Copyright (C) 1988-2021 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with the Invariant Sections being "Free Software" and "Free Software Needs Free Documentation", with the Front-Cover Texts being "A GNU Manual," and with the Back-Cover Texts as in (a) below. (a) The FSF's Back-Cover Text is: "You are free to copy and modify this GNU Manual. Buying copies from GNU Press supports the FSF in developing GNU and promoting software freedom." --> <!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ --> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>M2 Scope (Debugging with GDB)</title> <meta name="description" content="M2 Scope (Debugging with GDB)"> <meta name="keywords" content="M2 Scope (Debugging with GDB)"> <meta name="resource-type" content="document"> <meta name="distribution" content="global"> <meta name="Generator" content="makeinfo"> <link href="index.html#Top" rel="start" title="Top"> <link href="Concept-Index.html#Concept-Index" rel="index" title="Concept Index"> <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> <link href="Modula_002d2.html#Modula_002d2" rel="up" title="Modula-2"> <link href="GDB_002fM2.html#GDB_002fM2" rel="next" title="GDB/M2"> <link href="M2-Checks.html#M2-Checks" rel="prev" title="M2 Checks"> <style type="text/css"> <!-- a.summary-letter {text-decoration: none} blockquote.indentedblock {margin-right: 0em} blockquote.smallindentedblock {margin-right: 0em; font-size: smaller} blockquote.smallquotation {font-size: smaller} div.display {margin-left: 3.2em} div.example {margin-left: 3.2em} div.lisp {margin-left: 3.2em} div.smalldisplay {margin-left: 3.2em} div.smallexample {margin-left: 3.2em} div.smalllisp {margin-left: 3.2em} kbd {font-style: oblique} pre.display {font-family: inherit} pre.format {font-family: inherit} pre.menu-comment {font-family: serif} pre.menu-preformatted {font-family: serif} pre.smalldisplay {font-family: inherit; font-size: smaller} pre.smallexample {font-size: smaller} pre.smallformat {font-family: inherit; font-size: smaller} pre.smalllisp {font-size: smaller} span.nolinebreak {white-space: nowrap} span.roman {font-family: initial; font-weight: normal} span.sansserif {font-family: sans-serif; font-weight: normal} ul.no-bullet {list-style: none} --> </style> </head> <body lang="en"> <a name="M2-Scope"></a> <div class="header"> <p> Next: <a href="GDB_002fM2.html#GDB_002fM2" accesskey="n" rel="next">GDB/M2</a>, Previous: <a href="M2-Checks.html#M2-Checks" accesskey="p" rel="prev">M2 Checks</a>, Up: <a href="Modula_002d2.html#Modula_002d2" accesskey="u" rel="up">Modula-2</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p> </div> <hr> <a name="The-Scope-Operators-_003a_003a-and-_002e"></a> <h4 class="subsubsection">15.4.9.8 The Scope Operators <code>::</code> and <code>.</code></h4> <a name="index-scope"></a> <a name="index-_002e_002c-Modula_002d2-scope-operator"></a> <a name="index-colon_002c-doubled-as-scope-operator"></a> <a name="index-_003a_003a_002c-in-Modula_002d2"></a> <p>There are a few subtle differences between the Modula-2 scope operator (<code>.</code>) and the <small>GDB</small> scope operator (<code>::</code>). The two have similar syntax: </p> <div class="smallexample"> <pre class="smallexample"> <var>module</var> . <var>id</var> <var>scope</var> :: <var>id</var> </pre></div> <p>where <var>scope</var> is the name of a module or a procedure, <var>module</var> the name of a module, and <var>id</var> is any declared identifier within your program, except another module. </p> <p>Using the <code>::</code> operator makes <small>GDB</small> search the scope specified by <var>scope</var> for the identifier <var>id</var>. If it is not found in the specified scope, then <small>GDB</small> searches all scopes enclosing the one specified by <var>scope</var>. </p> <p>Using the <code>.</code> operator makes <small>GDB</small> search the current scope for the identifier specified by <var>id</var> that was imported from the definition module specified by <var>module</var>. With this operator, it is an error if the identifier <var>id</var> was not imported from definition module <var>module</var>, or if <var>id</var> is not an identifier in <var>module</var>. </p> </body> </html>