怀疑在C套接字程序中定义结构

Question

  data_size = recvfrom(sock_raw , buffer , 1024, 0 , &saddr ,
                                               (socklen_t*)&saddr_size);

Here is a recvfrom function, where I want to create a struct to 'saddr' and 'saddr_size' which is declared in the main() as follows

  struct sockaddr saddr;
  int saddr_size;
  saddr_size = sizeof saddr;

and instead of buffer mentioned in the below write() api I have to use the struct variable.

  int cont= write(logfile,buffer,data_size);

My question is: Below I have used structure. Is this the way to define struct for the following fields? Is it declared correctly? If not please somebody guide me to correct it.

  struct data{ 
      unsigned char buffer[1024];
      unsigned long int saddr; 
      //   struct sockaddr saddr;
      int saddr_size;
  }; 

Answer 1

I assumed this as your structure.

struct fields{ 
    unsigned char msg[1024];      // buffer received.
    char saddr[14];               // network socket address received.
    int sock_size;                // sizeof socket structure.
}data; 

After the recvfrom call, define/initialize your structure variables(ie, copy buffer,network address, size to the structure fields).

Now, log the structure data to the file

fprintf(logfile,"%s %s %d",data.msg,data.saddr.address,data.saddr_size);