SK/processes/c-cipc.c

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C
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2023-01-28 13:34:00 +01:00
#include <unistd.h>
#include <stdio.h>
#include <sys/uio.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
const char *main_path = "/tmp/serweripcmain";
typedef struct DanePid
{
long mtype; /* Message type. */
pid_t pid; /* Message text. */
} dane_pid;
typedef struct DaneDouble
{
long mtype; /* Message type. */
double n; /* Message text. */
} dane_double;
int main(int argc, char *argv[])
{
key_t key;
ssize_t bytes;
if (access(main_path, F_OK) == -1)
{
perror("file inaccessible");
return -1;
}
if ((key = ftok(main_path, 1)) == -1)
{
perror("main ftok error");
return -1;
}
int msg_id;
if ((msg_id = msgget(key, 0600)) == -1)
{
perror("msgget error");
return -1;
}
dane_pid pid;
pid.pid = getpid();
pid.mtype = 1;
dane_double test_dane;
test_dane.n = 12;
test_dane.mtype = 2;
if (msgsnd(msg_id, (const void *)&pid, sizeof(pid_t), 0) == -1)
{
perror("pid error");
return -1;
}
printf("Sent %d bytes pid: %d\n", sizeof(pid_t), pid.pid);
key_t key2;
if ((key2 = ftok(main_path, pid.pid)) == -1)
{
perror("data ftok error");
return -1;
}
int msg_id_2;
if ((msg_id_2 = msgget(key2, 0600 | IPC_CREAT | IPC_EXCL)) == -1)
{
perror("data msgget error");
return -1;
}
printf("Opened queue with id %x\n", msg_id_2);
if (msgsnd(msg_id_2, (const void *)&test_dane, sizeof(double), 0) == -1)
{
perror("data send error");
return -1;
}
printf("Sent %d bytes data: %f\n", sizeof(double), test_dane.n);
if ((bytes = msgrcv(msg_id_2, (void *)&test_dane, sizeof(double), 3, 0)) == -1)
{
perror("msgrcv error");
msgctl(msg_id, IPC_RMID, NULL);
return -1;
}
printf("Child received %d bytes and value %f\n", bytes, test_dane.n);
}