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PO"undefined reference to" error. (from a member function to static member variable)
 

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  1. PO"undefined reference to" error. (from a member function to static member variable)
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    <p>I got a following error upon linking.</p> <p>A member variable ClassBB::THR can't be accessed from a function ClassBB::bound(). </p> <p>What's strange is, from ClassBB::setThreshold(T v) function, which seems in the same condition with ClassBB::bound() in that both are template member function, ClassBB::THR is successfully accessed (I'm only talking about compile time, of course).</p> <p>I'm still new to C++ especially in template architecture. Thanks!</p> <p>Environment: Ubuntu 10.10, G++ 4.4.5 via Eclipse Indigo CDT</p> <p>Error msg (only linker's part):</p> <pre><code>Building target: SampleEclipsePrj Invoking: GCC C++ Linker g++ -L/usr/local/lib -L/usr/lib -o "SampleEclipsePrj" ./src/SampleEclipsePrjFinal/IntersectAngle.o ./src/SampleEclipsePrjFinal/ReadRealTime.o ./src/SampleEclipsePrjFinal/SampleEclipsePrj.o ./src/SampleEclipsePrjFinal/SampleEclipsePrjThread.o ./src/SampleEclipsePrjFinal/Slope.o ./src/SampleEclipsePrjFinal/Transform.o ./src/SampleEclipsePrjFinal/Utility.o ./src/SampleEclipsePrjFinal/main3_linux.o ./src/SampleEclipsePrjFinal/reader.o -lcv -lcxcore -lhighgui ./src/SampleEclipsePrjFinal/SampleEclipsePrj.o: In function `ClassBB&lt;double&gt;::bound()': /home/user/Documents/workspace_eclipse/SampleEclipsePrj/Includes/ClassBB.hpp:203: undefined reference to `ClassBB&lt;double&gt;::THR' /home/user/Documents/workspace_eclipse/SampleEclipsePrj/Includes/ClassBB.hpp:204: undefined reference to `ClassBB&lt;double&gt;::THR' /home/user/Documents/workspace_eclipse/SampleEclipsePrj/Includes/ClassBB.hpp:206: undefined reference to `ClassBB&lt;double&gt;::THR' /home/user/Documents/workspace_eclipse/SampleEclipsePrj/Includes/ClassBB.hpp:207: undefined reference to `ClassBB&lt;double&gt;::THR' collect2: ld returned 1 exit status make: *** [SampleEclipsePrj] Error 1 **** Build Finished **** </code></pre> <p>Note: Got the same result both on Eclipse and terminal.</p> <p>Code-B (snipped to show related part only):</p> <pre><code>#ifndef _BBOUND_H #define _BBOUND_H template&lt;class T&gt; class ClassBB { T *pMap; float u1, v1, u2, v2; int w, h; float converge(float sp, float ep, float steps, float fixedPt, float thr); static T THR; public: ClassBB() : pMap(NULL), u1(0), v1(0), u2(0), v2(0), w(0), h(0) { } ClassBB(float U1, float V1, float U2, float V2); static void setThreshold(T v); int bound(); ~ClassBB(); }; template&lt;class T&gt; ClassBB&lt;T&gt;::ClassBB(float U1, float V1, float U2, float V2) {// do something } template&lt;class T&gt; void ClassBB&lt;T&gt;::setThreshold(T v) { ClassBB::THR = v; } //Converge template&lt;class T&gt; float ClassBB&lt;T&gt;::converge(float sp, float ep, float step, float fixedPt, float thr) {// do something return point; } //The bound algorithm template&lt;class T&gt; int ClassBB&lt;T&gt;::bound() { u2 = converge(0.75, 0.5, 0.03125, v2, ClassBB::THR); v2 = converge(0.25, 0.0, 0.03125, u2, THR); // Both don't work. return 1; } template&lt;class T&gt; ClassBB&lt;T&gt;::~ClassBB() {// do something } #endif </code></pre> <p>Code-C (instantiate the class):</p> <pre><code>#ifndef _SCENE_CLASSIFIER_H #define _SCENE_CLASSIFIER_H #include "ClassBB.hpp" class ClassCC { ClassBB&lt;double&gt; bb; //Branch and Bound public: ClassCC(int W = 0, int H = 0); ~ClassCC(); }; #endif </code></pre>
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    1. PO
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    1. This table or related slice is empty.
    1. PTQuestion
    1. USLightness Races in Orbit
    1. USIsaacS
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
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    2. PO
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    1. VO
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      1. PO"undefined reference to" error. (from a member function to static member variable)
      1. This table or related slice is empty.
      1. VTUpMod
    1. COWhere is the code which instantiates `ClassBB<double>`?
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      1. PO"undefined reference to" error. (from a member function to static member variable)
      1. USwallyk
    2. COSorry now it's added as Code-C where ClassBB<double> is instantiated.
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      1. PO"undefined reference to" error. (from a member function to static member variable)
      1. USIsaacS
    3. COI have edited the question title, as that error cannot happen with a non-static member variable.
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      1. PO"undefined reference to" error. (from a member function to static member variable)
      1. USDavid Rodríguez - dribeas
 

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