dlOpenTest.c

#include <stdio.h>
#include <dlfcn.h>  // dlopen, dlsym
#include <string.h> // memset

#define REAL double

struct triangulateio {
  REAL *pointlist;                                               /* In / out */
  REAL *pointattributelist;                                      /* In / out */
  int *pointmarkerlist;                                          /* In / out */
  int numberofpoints;                                            /* In / out */
  int numberofpointattributes;                                   /* In / out */

  int *trianglelist;                                             /* In / out */
  REAL *triangleattributelist;                                   /* In / out */
  REAL *trianglearealist;                                         /* In only */
  int *neighborlist;                                             /* Out only */
  int numberoftriangles;                                         /* In / out */
  int numberofcorners;                                           /* In / out */
  int numberoftriangleattributes;                                /* In / out */

  int *segmentlist;                                              /* In / out */
  int *segmentmarkerlist;                                        /* In / out */
  int numberofsegments;                                          /* In / out */

  REAL *holelist;                        /* In / pointer to array copied out */
  int numberofholes;                                      /* In / copied out */

  REAL *regionlist;                      /* In / pointer to array copied out */
  int numberofregions;                                    /* In / copied out */

  int *edgelist;                                                 /* Out only */
  int *edgemarkerlist;            /* Not used with Voronoi diagram; out only */
  REAL *normlist;                /* Used only with Voronoi diagram; out only */
  int numberofedges;                                             /* Out only */
};

int main()
{
  // Signature for the triangulation function in `triangle.dylib`.
  void (*triangulateFn)(char *, struct triangulateio *, struct triangulateio *, struct triangulateio *);
  // Open the library.
  void* handle = dlopen("triangle.dylib", RTLD_LAZY);
  // Fetch the function.
  *(void**)(&triangulateFn) = dlsym(handle, "triangulate");

  struct triangulateio in, out;
  memset(&in, 0, sizeof(struct triangulateio));
  memset(&out, 0, sizeof(struct triangulateio));

  double vertices[8] = {0, 0, 512, 0, 612, 668, 100, 668};
  in.numberofpoints = 4;
  in.pointlist = (vertices);

  int edges[8] = {0, 1, 1, 2, 2, 3, 3, 0};
  in.numberofsegments = 4;
  in.segmentlist = (edges);

  triangulateFn("pzenQ", &in, &out, NULL);

  printf("Got these many points %d\n", out.numberofpoints);
  for(int i = 0; i < out.numberofpoints; i++)
  {
    int idx = i*2;
    printf("Point %d: %.2f, %.2f\n", i, out.pointlist[idx], out.pointlist[idx+1]);
  }

  printf("Got these many segments: %d\n", out.numberofsegments);
  for(int i = 0; i < out.numberofsegments; i++)
  {
    int idx = i*2;
    printf("Segment %d: %d, %d\n", i, out.segmentlist[idx], out.segmentlist[idx+1]);
  }

  return 0;
}