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I thought is was a builtin type. But a simple snippet of code in C++ using visual studio 2008 is complaining that it is an unreferenced local variable when i do <br />
bool myBoolVar;
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By any chance did your file have a .c extension. ANSI C-language does not have bool intrinsically defined.<br />
If you want, you can post the small snippet and we'll see if it runs it builds in different environments.
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The <b>bool</b> is a keyword in C++. You cannot redefine it. If you read that in your old source, it is probably a C source -- as phoffric said. If you want to have <i>syntactically</i> the same <b>bool</b> type and <b>true</b> and <b>false</b> constants, you can add elsewhere code like this:<br />
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<pre><code class="code-1 nolinks" id="code-20-41780540-1"><span>#ifndef __cplusplus</span>
<span>typedef unsigned char bool;</span>
<span>static const bool false = 0;</span>
<span>static const bool true = 1;</span>
<span>#endif</span>
</code></pre>
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The <b>__cplusplus</b> symbol (two underscores) is defined by the any C++ compiler for solving the situations like this. The code says: If the symbol is not defined (that is we use a C compiler [setting]), then define the bool type using the standard C way. Define also the constants. If the symbol <i>is</i> defined, then the lines are skipped and the built-in type and values (keywords) are used.<br />
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I did not check, whether bool became also keyword in later C standards. In such case, the above construct would colide even with C.
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good observation pepr.<br />
Would also have helped if the author had used the word, &quot;<i>warning</i>&quot;. I took <i>complaining </i>too strongly as in <i>error</i>.
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No comment has been added to this question in more than 21 days, so it is now classified as abandoned.<br />
<br />
I have recommended this question be closed as follows:<br />
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Accept: pepr (<a href="https:#a41801075" rel="ugc">https:#a41801075</a>)<br />
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If you feel this question should be closed differently, post an objection and the moderators will review all objections and close it as they feel fit. If no one objects, this question will be closed automatically the way described above.<br />
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frankhelk<br />
Experts-Exchange Cleanup Volunteer
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Hi<br />
<br />
what's the most standard lib that defines this for C++? and for c+11?<br />
<br />
thanks
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Hi

what's the most standard lib that defines this for C++? and for c+11?

thanks

bool defined where?

C++ is an intermediate-level general-purpose programming language, not to be confused with C or C#. It was developed as a set of extensions to the C programming language to improve type-safety and add support for automatic resource management, object-orientation, generic programming, and exception handling, among other features.