How can I import .csv file data into gsl_vectors in C++?

Question

I have a .csv file that looks like:

X,Y,Z
0,0,0
0,0,0
-0.00624347,-0.0182673,1.00063
-0.00845628,-0.0374925,1.00058
-0.00494793,-0.0295639,0.927447
-0.00285682,-0.0926582,0.885783
-0.00832563,-0.02957,0.697834

And I want to put it into three gsl_vectors (from GSL: https://www.gnu.org/software/gsl/doc/html/vectors.html) corresponding to the column X, column Y and column Z respectively. The reason why I want to do this is because I later want to use the functions that are implemented in the GNU Scientific Library on this data. I want to emphasize that these functions can only work on gsl_vectors and not on std:vectors.

My approaches:

1. Put the data from the .csv into std:vectors, and then transform those vectors into gsl_vectors. That did not work.

2. Put the data from the .csv file into gsl_vectors directly:

   #include <iostream>
   #include <fstream>
   #include <istream>
   #include <string>
   #include <sstream>
   #include <algorithm>
   #include <gsl/gsl_linalg.h>
   #include <gsl/gsl_vector.h>
   
   struct acceleration {
       gsl_vector AccX;
       gsl_vector AccY;
       gsl_vector AccZ;
   };
   
   // Function prototypes
   acceleration read_csv(acceleration& A);
   // End function prototypes
   
   int main(void)
   {
       // ==================READ THE CSV=========================
       acceleration data;
       data = read_csv(data);
       printf("/n");
       gsl_vector_fprintf(stdout, &data.AccX, "%lf");
   
       return 0;
   }
   
   acceleration read_csv(acceleration& SA)
   {
       std::string buffer; /* Declare a buffer for the data that will be read */
       std::string bacx, bacy, bacz;
       std::ifstream inputfile;
       inputfile.open("buffer.csv"); /* Open file for reading */
       if (!inputfile.is_open())
       {
           std::cout << "Error opening file" << std::endl;
       }
   
       std::stringstream aux(buffer);
       getline(aux, bacx, ',');
       getline(aux, bacy, ',');
       getline(aux, bacz, ',');
       size_t i{ 0 };
   
       while (getline(inputfile, buffer))
       {
           std::stringstream aux(buffer);
   
           getline(aux, bacx, ',');
           if (bacx.compare("AX") != 0)
               gsl_vector_set(&SA.AccX, i, stod(bacx));
   
           getline(aux, bacy, ',');
           if (bacy.compare("AY") != 0)
               gsl_vector_set(&SA.AccY, i, stod(bacy));
   
           getline(aux, bacz, ',');
           if (bacz.compare("AZ") != 0)
               gsl_vector_set(&SA.AccZ, i, stod(bacz));
           i++;
       }
       inputfile.close();
       return (SA);
   
   }
   

   This gives no output on the Console and if I debug it, the function gsl_vector_set throws an exception:

   Exception thrown at 0x7A5EED1A (gsld.dll) in progr.exe: 0xC0000005: Access violation writing location 0x3333332

   At gsl_set_vector's line: v->data[i * v->stride] = x;

3. Put the .csv data into a gsl_block and then slice it into gsl_vectors. Here I get an exception when trying to put the data into the block. Then, for slicing the block into vectors, I assume I'll have to use the gsl_vector_alloc_from_block() function, yet I did not find any example on how to use this function. I do need to see how others use functions generally because I'm new to C++. Here is what I have until now for this idea:

   #include <iostream>
   #include <fstream>
   #include <gsl/gsl_linalg.h>
   #include <gsl/gsl_vector.h>
   
   // Function prototypes
   gsl_block read_csv(void);
   // End function prototypes
   
   int main(void)
   {
       // ================== READ THE CSV INTO A BLOCK =========================
       gsl_block data;
       data = read_csv();
       // ================= NOW SLICE THE BLOCK: HOW? ==========================
       // Use gsl_vector_alloc_from_block(), but how?
       return 0;
   }
   
   // Function declarations
   gsl_block read_csv(void)
   {
       FILE* inputfile;
       fopen_s(&inputfile, "buffer.csv", "r"); /* Open file for reading */
       if (inputfile == NULL)
           std::cout << "file does not exist \n";
       fseek(inputfile, 0L, SEEK_END); // Go until the end
       int file_size = ftell(inputfile); // In order to tell the size of the file
       gsl_block* b = gsl_block_alloc(file_size);
       if(inputfile)
           gsl_block_fscanf(inputfile, b);
   
       fclose(inputfile);
   
       return *b;
   
   }
   // End function declarations
   

   If I run this I get:

   Debug Error! abort() has been called

   And on the Console it is shown:

   gsl: C:\DEV\vcpkg\buildtrees\gsl\src\gsl-2-fb511965d5.clean\block\fprintf_source.c:90: ERROR: fscanf failed Default GSL error handler invoked.

   If I debug this, the gsl_error function throws an exception:

   progr.exe has triggered a breakpoint.

   At abort ();

To sum up, I actually want to read the .csv file into gsl_vectors. If my approaches are not OK, it is understandable.