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POHaving trouble accessing struct elements returned by a function - dereferencing pointer to incomplete type
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copied!<p>I am new to C.This are the files and codes that I am working on. I am trying to call a function (refineMatch) implemented in a separate file from the main function. function refineMatch returns a struct. I am having problems in compiling the code which is related to accessing elements in the returned struct. The compile error occurs in main.c file. Code below shows where the error happens.</p> <p>refine.h</p> <pre><code>#include <cv.h> #include <cxcore.h> #include <highgui.h> struct matchingpair{ CvPoint p1, p2; }; struct matchingpair_array{ struct matchingpair* elements; int length; }; struct matchingpair_array *refineMatch(struct matchingpair* pairs,int pointcount, int bestpair); </code></pre> <p>refine.c</p> <pre><code>#include "refine.h" #include "utils.h" #include <stdlib.h> struct matchingpair_array *refineMatch(struct matchingpair* pairs,int pointcount, int bestpoint){ struct matchingpair_array refinedPairs; refinedPairs.elements=malloc(incount*sizeof(struct matchingpair)); int *in=malloc(pointcount*sizeof(int)), i=0,incount=8; // several statements - including filling in[] with data for(i=0;i<incount;i++){ refinedPairs.elements[i]=pairs[in[i]]; fprintf(stderr,"%d\n",in[i]); } refinedPairs.length=incount; free(in); // several other free() operations non include refinedPairs or elements return &refinedPairs; } </code></pre> <p>main.c</p> <pre><code>#include "refine.h" #include <stdio.h> int main( int argc, char** argv ){ struct matchingpair* pairs; int matchcount=0,bestpair; pairs=(struct matchingpair*)malloc(pairArrSize*sizeof(struct matchingpair)); //values are assigned to pairs, matchcount and bestpair struct matcingpair_array* result=(struct matcingpair_array*)refineMatch(pairs,matchcount,bestpair); /*(casting removed this warining) warning: initialization from incompatible pointer type*/ fprintf(stderr,"%d \n",result->length); //error: dereferencing pointer to incomplete type //some other code } </code></pre> <p>Please explain me what I am doing wrong here. I am using gcc.<br /> Thank you.</p>

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