Document Message Queue variables.

[wsti_so.git] / src / process3.c

diff --git a/src/process3.c b/src/process3.c
index a012f4c5616dd525826c03dbbe6cc33723ebde96..91212e991a1cc3ff0363e1a8f157fa5df5a7bc8b 100644 (file)
--- a/src/process3.c
+++ b/src/process3.c
@@ -35,7 +35,8 @@ key_t shmkey = 18912;
 int shmid;
 
 /**
- * Message shared by processes. Contains array of process IDs
+ * Structure holding array of process IDs.
+ * Message is shared by processes. Contains array of process IDs
  */
 struct message {
        pid_t pids[3];
@@ -44,14 +45,24 @@ struct message {
 struct message * processes = NULL;
 
 /**
- * Message queue variables
+ * Message Queue variables
  */
-key_t qkey;
-int qid_input;
 
-int qid_output1;
-int qid_output2;
+/**
+ * Unique key of message queue.
+ */
+key_t qkey = 12356;
 
+/**
+ * Queue descriptor.
+ */
+int qid;
+
+/**
+ * Structure holding queue message data.
+ * Parameter mtype describes process to whom message is sent.
+ * Parameter signo is a signal to raise after getting message.
+ */
 struct queue_message {
        long mtype;
        int signo[1];
@@ -68,7 +79,7 @@ void notify_other_processes(int signo) {
                if (i != 2 && pid != 0) {
                        msg.mtype = i+1;
                        fprintf(stderr, "[%s] Sending message of type (%d) with value %d\n", "process3", msg.mtype, msg.signo[0]);
-                       msgsnd(pid, &msg, sizeof(int), 0);
+                       msgsnd(qid, &msg, sizeof(int), 0);
                        fprintf(stderr, "[%s] Sending signal %s (%d) to PID: %d\n", "process3", strsignal(SIGUSR1), SIGUSR1, pid);
                        kill(pid, SIGUSR1);
                }
@@ -80,20 +91,14 @@ void notify_other_processes(int signo) {
  */
 void sig_handler(int signo)
 {
-       fprintf(stderr, "[%s] Received !\n", "process3");
+       fprintf(stderr, "[%s] Received %s!\n", "process3", strsignal(signo));
        if (signo == SIGUSR1) {
                fprintf(stderr, "[%s] > Notified!\n", "process3");
                struct queue_message msg;
                /* Check queues from both other processes */
-               if (msgrcv(processes->pids[0], &msg, sizeof(int), 3, 0) > 0) {
+               if (msgrcv(qid, &msg, sizeof(int), 3, 0) > 0) {
                        fprintf(stderr, "[%s] > Notified with value: %s!\n", "process3", strsignal(msg.signo[0]));
                        raise(msg.signo[0]);
-                       break;
-               }
-               else if (msgrcv(processes->pids[1], &msg, sizeof(int), 3, 0) > 0) {
-                       fprintf(stderr, "[%s] > Notified with value: %s!\n", "process3", strsignal(msg.signo[0]));
-                       raise(msg.signo[0]);
-                       break;
                }
        }
        else if (signo == SIGTERM) {
@@ -165,11 +170,7 @@ int main(void) {
        /**
         * Register message queue to communicate with other processes
         */
-       qkey = getpid();
-       qid_input = msgget(qkey, IPC_CREAT | 0666);
-       
-       qid_output1 = msgget(processes->pids[1], IPC_CREAT | 0666);
-       qid_output2 = msgget(processes->pids[2], IPC_CREAT | 0666);
+       qid = msgget(qkey, 0666);
 
        /* Reading from process2 */
        read_descriptor = open(read_pipe, O_RDONLY);