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core/com.nokia.carbide.cpp.compiler.doc.user/html/errors/err_common.htm
author timkelly
Thu, 10 Dec 2009 13:45:47 -0600
branchRCL_2_4
changeset 671 80524b72f957
parent 0 fb279309251b
child 1641 2b3996fc09a1
permissions -rw-r--r--
Add S60 5.2 support.
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN"><html>
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
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<meta http-equiv="Content-Style-Type" content="text/css" />
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<meta name="LASTUPDATED" content="06/17/05 11:09:43" />
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<title>Common Errors</title>
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<link rel="StyleSheet" href="../../book.css" type="text/css"/>
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</head>
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<body bgcolor="#FFFFFF">
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<h3>Common Errors</h3>
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<p>  If you enable the Possible Errors setting, the compiler generates a warning if it encounters common errors such as the following:</p>
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<ul>
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  <li>An assignment in either a logical expression or the conditional portion of an if, while, or for expression. This warning is useful if you use = when you mean to use ==. An example of confusing = and == in comparisons:</li>
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</ul>
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<blockquote>
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  <p class="listing">    if (a=b) f(); // WARNING: a=b is an assignment<br />
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    if ((a=b)!=0) f(); // OK: (a=b)!=0 is a comparison, no warning<br />
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  if (a==b) f(); // OK: (a==b) is a comparison, no warning</p>
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</blockquote>
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<ul>
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  <li>An equal comparison in a statement that contains a single expression. This check is useful if you use == when you meant to use =. An example of confusing = and == operators in assignments:</li>
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</ul>
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<blockquote>
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  <p class="listing">    a == 0; // WARNING: This is a comparison.<br />
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  a = 0; // OK: This is an assignment, no warning</p>
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</blockquote>
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<ul>
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  <li>A semicolon (;) directly after a while, if, or for statement. For example, the following statement generates a warning and is probably an unintended infinite loop:</li>
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</ul>
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<blockquote>
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  <p class="listing">while (i++); // WARNING: Unintended infinite loop</p>
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  <p>If you intended to create an infinite loop, put white space or a comment between the while statement and the semicolon.</p>
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  <p>These statements suppress the above errors or warnings.</p>
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  <p class="listing">while (i++) ; // OK: White space separation, no warning<br />
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    while (i++) /*: Comment separation, no warning */ ;</p>
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</blockquote>
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<p>The Possible Errors setting corresponds to the pragma <a href="../pragmas/p_warn_possunwant.htm">warn_possunwant</a>. To check this setting, use <span class="code">__option (warn_possunwant)</span>.</p>
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<p> See <a href="../symbols/sym_settings.htm">Checking Option Settings</a> for information on how to use this directive.<br />
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</p>
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<div id="footer">Copyright &copy; 2009 Nokia Corporation and/or its subsidiary(-ies). All rights reserved. <br>License: <a href="http://www.eclipse.org/legal/epl-v10.html">http://www.eclipse.org/legal/epl-v10.html</a></div>
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FCL/sftools/dev/ide/carbidecpp