Hello-- I'm writing a perl extension in C. I want to send an array from the C function back to the main Perl section of the code. I've tried recasting my float array to a char * string, but i seem unable to get the packed array back out to Perl. Here is the code i have thus far (this is the XSUB function, as I don't think the perl code is the problem at this point, since the packed array seems to contain nothing: 

MODULE = f  PACKAGE = f  

#include "math.h"
#define PI 3.1459

char *
f(rows, cols, packedmatrix)
 int rows
 int cols
 char * packedmatrix
 CODE:
 float **M;
 float len1, len2, dotproduct;
 int k1;
 int k2;    
  int k3;
      float theta;
 float product;
 char * packedangles;
 float angles[cols][cols];
 M = (float**)packedmatrix;
 for (k1 = 0; k1<(cols-1); ++k1) {
  for (k2 = (k1+1); k2<(cols); ++k2) {
        dotproduct = 0;
        len1 = 0;
        len2 = 0;
        for (k3 = 0; k3 < rows; ++k3) {
        if ((M[k3][k1] != 999) && (M[k3][k2] != 999)) {
        dotproduct = dotproduct + (M[k3][k1])*(M[k3][k2]);
        len1 = len1 + pow((M[k3][k1]), 2);
        len2 = len2 + pow((M[k3][k2]), 2);
   }
     } 
     theta = 180*(acos(dotproduct/sqrt(len1*len2)))/PI;
     angles[k1][k2]=theta;
     printf("The angle between columns %d and columns %d is %f\n\n", k
+1, k2, theta);
 }

 packedangles = (char*)angles;
 printf("Packed angles: %s", packedangles);
 RETVAL = packedangles;
}
 OUTPUT: RETVAL

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Any help would be most most appreciated. Thanks! Evan

In reply to Sending packed data from C to Perl by Evanovich

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