how to send structure in C using UDP sockets without serialization?

Question

I am trying to send a structure in C without using serialization

// client
typedef struct student_rec {
char name[25];
float gpa;
int pid;
} stu;

stu stu = { "Ray T Champion" , 4.0 ,  12345666};

sendto(sk,&stu,sizeof(struct student_rec),0,&remote,sizeof(remote));




//server
typedef struct student_rec {
char name[25];
float gpa;
int pid;
} stu;

stu s ;
struct student_rec *ptr;
ptr = &s;
recvfrom(sk,&s,sizeof(struct student_rec),0,&remote,&rlen);
printf("%s\n", ptr->name);
printf( "%d\n", ptr->pid );

I recieve the name just fine , but the pid is not correct, I get garbage values, I am not concerend about endianess, I would just like to be able to send the struct in one shot.

Answer 1

You face an endianess issue.

You send 12345666 which is the same as 0x00BC6142

and you receive 1113701376 which equal to 0x4261BC00 .

Before sending convert to network byte order by

stu.pid = htonl(stu.pid);

After receiving convert (back) to host byte order.

stu.pid = ntohl(stu.pid);