Implementing a Matlab Reader using winsock2 and DLL library

Question

I am trying to interface Matlab with a C code that I used to read data through UDP. I am using the winsock2 library, and compiling the C code into a DLL file for it to be loaded into Matlab. My C code is working fine and reading the udp data as expected. But when I use the same code via'loadlibrary' function in Matlab, it just returns me all zeroes. The problem is definitely on the MATLAB side since I have already verified C code to be working and reading data properly. Does anyone have an idea of what I am doing wrong? My C code, header file and Matlab script are given below:

C code:

``#include <stdio.h>
#include <stdlib.h>
#include <winsock2.h>
#include <windows.h> // Include for Sleep function
#include "udpfunc2.h" 
#define BUFLEN 48
SOCKET s;
// Function to initialize UDP socket
int init_udp_socket() {
  WSADATA wsaData;
if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
    printf("WSAStartup failed\n");
    return -1;
}
return 0;
}
// Function to create and bind UDP socket
int create_udp_socket() {
if ((s = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)) == INVALID_SOCKET) {
    printf("Socket creation failed\n");
    return -1;
}
return 0;
}
// Function to bind UDP socket to specified IP address and port
int bind_udp_socket(const char *ip_address, int port) {
struct sockaddr_in server;
server.sin_family = AF_INET;
server.sin_addr.s_addr = inet_addr(ip_address);
server.sin_port = htons(port);
if (bind(s, (struct sockaddr *)&server, sizeof(server)) == SOCKET_ERROR) {
    printf("Bind failed\n");
    return -1;
}
return 0;
}
// Function to set socket to non-blocking mode
int set_socket_nonblocking() {
unsigned long mode = 1; // 1 to enable non-blocking mode
if (ioctlsocket(s, FIONBIO, &mode) != 0) {
    printf("Failed to set socket to non-blocking mode\n");
    return -1;
}
return 0;
}
// Function to continuously read data through UDP as 12 single values (non-blocking)
void udp_read_continuous(float *data) {
struct sockaddr_in si_other;
int slen = sizeof(si_other);
int recv_len;
//zero out the memory buffer
memset(data,0,12 * sizeof(float));

recv_len = recvfrom(s, (char *)data, BUFLEN, 0, (struct sockaddr *)&si_other, &slen);
    
// Convert data from big-endian to host byte order
// Assuming each single value is a 32-bit float
for (int i = 0; i < 12; i++) {
    unsigned int val;
    memcpy(&val , &data[i], sizeof(float));
    val = ntohl(val);
    data[i] = *((float*)&val);
}
// Print received data
printf("Received data: ");
for (int i = 0; i < 12; i++) {
    printf("%.6f ", data[i]);
}
printf("\n");

}
// Function to close UDP socket
void close_udp_socket() {
closesocket(s);
WSACleanup();`
}

` Header File:

`#ifndef UDP_FUNC2_H
#define UDP_FUNC2_H
#include <winsock2.h>
#ifdef __cplusplus
extern "C" {
#endif
// Function prototypes
int init_udp_socket();
int create_udp_socket();
int bind_udp_socket(const char *ip_address, int port);
int set_socket_nonblocking();
void udp_read_continuous(float *data);
void close_udp_socket();
#ifdef __cplusplus
}
#endif
#endif // UDP_FUNC2_H`

MATLAB Script

```clc;
clear;
if libisloaded('udpfunc2')
unloadlibrary('udpfunc2')
end
loadlibrary('udpfunc2.dll', 'udpfunc2.h');
% Define UDP parameters
ip_address = '127.0.0.1'; % Local IP address
localPort = 44444; % Example port number

% Initialize UDP socket
status = calllib('udpfunc2', 'init_udp_socket');
if status == 0
disp('UDP socket initialized successfully');
else
disp('Failed to initialize UDP socket');
return;
end
% Open UDP socket
status = calllib('udpfunc2', 'create_udp_socket');
if status == -1
disp('Failed to Open UDP Socket');
end
% Bind UDP Socket to Local Port and IP address
status = calllib('udpfunc2', 'bind_udp_socket', ip_address, localPort);
if status == 0
disp('UDP socket binded successfully');
else
disp('Failed to bind socket');
return;
end
% Set Socket to Non-Blocking
status = calllib('udpfunc2', 'set_socket_nonblocking');
if status == 0
disp('UDP socket set to Non-Blocking successfully');
else
disp('Failed to set socket to Non-Blocking');
return;
end
% Create a MATLAB struct to hold the 12 single values
dataPacket = zeros(1, 12, 'single');
% Read continuous UDP data
while true
calllib('udpfunc2', 'udp_read_continuous', dataPacket);
fprintf('%.6f\n', dataPacket(12));
end
% Close UDP socket
calllib('udpfunc2', 'close_udp_socket');
disp('UDP socket closed');`
% Unload the DLL
unloadlibrary('udpfunc2');

` Receiving no data for udp read on Matlab