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# C++ Source Code Analyzer Example

Files:

- xmlpatterns/xquery/globalVariables/globals.cpp
- xmlpatterns/xquery/globalVariables/reportGlobals.xq
- xmlpatterns/xquery/globalVariables/globalVariables.pro

The C++ source code analyzer example shows how to write a real world XQuery query.

## Overview

Sometimes it is of use to analyze C++ code, in order to find common mistakes & patterns. For that one can use search & text utilites like `grep` on UNIX, or try to write ones own C++ parser and subsequently do search there.

But what if there were a simpler but still as correct approach?

g++, the open source C++ compiler, has an extension called GCC-XML that outputs the declarations in a compilation unit(a C++ file) in XML. Since that "C++ to XML" conversion is done with GCC itself, it means the parsing of the C++ code is done with one of the best C++ parsers on this planet.

Once the C++ is in XML, a query can swiftly navigate it to produce a report.

## Global variables

Usually one wants to avoid global mutable variables in C++, since they have a state globally and therefore often is a source to bugs, especially related to threading.

For instance, in globals.cpp, the global, mutable integers as well as the global class instances should preferrably be avoided:

     /****************************************************************************
     **
     ** Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies).
     ** Contact: Qt Software Information (qt-info@nokia.com)
     **
     ** This file is part of the example classes of the Qt Toolkit.
     **
     ** Commercial Usage
     ** Licensees holding valid Qt Commercial licenses may use this file in
     ** accordance with the Qt Commercial License Agreement provided with the
     ** Software or, alternatively, in accordance with the terms contained in
     ** a written agreement between you and Nokia.
     **
     **
     ** GNU General Public License Usage
     ** Alternatively, this file may be used under the terms of the GNU
     ** General Public License versions 2.0 or 3.0 as published by the Free
     ** Software Foundation and appearing in the file LICENSE.GPL included in
     ** the packaging of this file.  Please review the following information
     ** to ensure GNU General Public Licensing requirements will be met:
     ** http://www.fsf.org/licensing/licenses/info/GPLv2.html and
     ** http://www.gnu.org/copyleft/gpl.html.  In addition, as a special
     ** exception, Nokia gives you certain additional rights. These rights
     ** are described in the Nokia Qt GPL Exception version 1.3, included in
     ** the file GPL_EXCEPTION.txt in this package.
     **
     ** Qt for Windows(R) Licensees
     ** As a special exception, Nokia, as the sole copyright holder for Qt
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     int mutablePrimitive1;
     int mutablePrimitive2;
     const int constPrimitive1 = 4;
     const int constPrimitive2 = 3;

     class ComplexClass
     {
     public:
         ComplexClass();
         ComplexClass(const ComplexClass &);
         ~ComplexClass();
     };

     ComplexClass mutableComplex1;
     ComplexClass mutableComplex2;
     const ComplexClass constComplex1;
     const ComplexClass constComplex2;

     int main()
     {
         int localVariable;
         localVariable = 0;
         return localVariable;
     }