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POUse global variables as parameters of a function allocated in other source file
 

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  1. POUse global variables as parameters of a function allocated in other source file
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    <p>I'm coding a program of openGL which read the points and the faces from a text file and later displays them on the screen.</p> <p>I do the opengl matters in main.cpp and I load the file in LoadFile.cpp.</p> <p>In the main, I have an array with the points that I'm going to display:<br/></p> <pre><code> Point3f* vertexContainer; int vertexn; </code></pre> <p>And I've declared the function that I'm going to use in order to load the source file:<br/></p> <pre><code>extern void loadFile(const char*,Point3f*, int, Face*, int); </code></pre> <p><i>Note that extern is not mandatory here. Don't care about faces, for the momment.</i></p> <p>Inside LoadFile.cpp:<br/></p> <pre><code>void loadFile(const char* path, Point3f* vertexContainer, int nvertex, Face* faceContainer, int nfaces) { //reading and processing source file, //storing the input vertices in: std::vector&lt;Point3f&gt; verticesVector. //Finally: vertexContainer = &amp;verticesVector[0]; vertexn = verticesVector.size(); } </code></pre> <p>And nothing is displayed on the screen. Also, If I debug vertexContainer, I realize that its value never changes.</p> <p>However, if I debug a local variable vc, I can see the changes:<br/></p> <pre><code>Point3f* vc = &amp;verticesVector[0]; </code></pre> <p>I have noticed that, if i pass by reference the array, it changes, but, mysteriously when the program control comes back to main, its values have changed wrongly!<br/> And I had thought that arrays never have to be passed by reference.</p> <p>The other approach is return the vector itself to the main, but prefer be able to work with arrays, once the file is processed.</p>
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    1. COI've just tried to return vector<Point3f> by reference and it works fine.
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