sendfile on macOS and gcc

Question

I am try to make most basic FTP feature in c language on macOS host mashine. I use g++ or gcc compiler. I found c example for linux but sendfile is not the same prototype like macos system support. I fix include with :

#if __APPLE__
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <sys/uio.h>
#elif
    #include <sys/sendfile.h>
#endif

• Interface:

OSX:  
    int sendfile(int fd, int s, off_t offset, off_t *len, struct sf_hdtr *hdtr, int flags);  
Linux: 
    ssize_t sendfile(int out_fd, int in_fd, off_t *offset, size_t count);

Whole file :

////FTP SERVER WITH TCP

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>

#include <sys/stat.h>

#if __APPLE__
    #include <sys/types.h>
    #include <sys/socket.h>
    #include <sys/uio.h>
#elif
    #include <sys/sendfile.h>
#endif

#include <fcntl.h>

/*
OSX:
  int sendfile(int fd, int s, off_t offset, off_t *len, struct sf_hdtr *hdtr, int flags);
Linux:
  ssize_t sendfile(int out_fd, int in_fd, off_t *offset, size_t count);
*/

int main()
{
  int sock_desc, sock_desc2;
  socklen_t len;
  struct stat obj;
  char length[10];
  int filehandle;
  char choice[100];
  int k, i;
  char buf[100];
  char target[100];
  struct sockaddr_in client, server;
  memset(&client, 0, sizeof(client));
  memset(&server, 0, sizeof(server));
  sock_desc = socket(AF_INET, SOCK_STREAM, 0);
  if (sock_desc == -1)
  {
    puts("Error in socket 1");
    exit(1);
  }
  server.sin_family = AF_INET;
  server.sin_addr.s_addr = INADDR_ANY;
  server.sin_port = 8045;

  k = bind(sock_desc, (struct sockaddr *)&server, sizeof(server));
  if (k == -1)
  {
    puts("Error in binding");
    exit(1);
  }
  k = listen(sock_desc, 5);
  if (k == -1)
  {
    puts("Error in listening");
    exit(1);
  }
  len = sizeof(client);
  sock_desc2 = accept(sock_desc, (struct sockaddr *)&client, &len);
  if (sock_desc2 == -1)
  {
    puts("Error in socket2");
    exit(1);
  }
  while (1)
  {
    k = recv(sock_desc2, buf, 100, 0);
    if (k == -1)
    {
      puts("Error in receive");
      exit(1);
    }
    for (i = 0; i < 4; i++)
    {
      choice[i] = buf[i];
    }
    choice[i] = '\0';
    puts("");
    puts(choice);
    puts("");
    if (strcmp(choice, "LIST") == 0)
    {
      system("ls -al>list.txt");
      filehandle = open("list.txt", O_RDONLY); //
      stat("list.txt", &obj);                  //
      sprintf(length, "%d", (int)obj.st_size);
      puts("sending size of file");
      k = send(sock_desc2, length, strlen(length), 0);
      if (k == -1)
      {
        printf("send failed");
        exit(1);
      }
      puts("send entire file");
      k = sendfile(sock_desc2, filehandle, NULL, obj.st_size);
      if (k == -1)
      {
        printf("file sendingfailed");
        exit(1);
      }
    }
    else if (strcmp(choice, "LOAD") == 0)
    {
      puts("inside load");
      strcpy(target, buf + 5);
      printf("target file is*%s*\n", target);
      memset(&obj, 0, sizeof(obj));
      stat(target, &obj);
      filehandle = open(target, O_RDONLY);
      if (filehandle == -1)
      {
        puts("Error in opening file for read");
        exit(1);
      }
      sprintf(length, "%d", (int)obj.st_size);
      k = send(sock_desc2, length, strlen(length), 0);
      if (k == -1)
      {
        puts("Error in sending");
        exit(1);
      }
      k = sendfile(sock_desc2, filehandle, NULL, obj.st_size);
      if (k == -1)
      {
        puts("Error in sending file");
        exit(1);
      }
    }
  }
}

UPDATE:

Ok, i wanted to make adaptation, to prepare args for sendfile also for macos. I count on thought 'it is a same compiler and linux and mac are based on UNIX' but it is not enough.

Look's like sockets feature also need totally different source and libs.

Question is simple transfer file in c on macos using gcc compiler.

I found interest imports:

#include <arpa/inet.h>
#include <netinet/in.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

Works on macos