stuff

Examples/ipc/ipcmsg_gfg_r.c

@@ -0,0 +1,39 @@
+// C Program for Message Queue (Reader Process)
+#include <stdio.h>
+#include <sys/ipc.h>
+#include <sys/msg.h>
+
+// structure for message queue
+struct mesg_buffer
+{
+    long mesg_type;
+    char mesg_text[100];
+} message;
+
+int main()
+{
+    key_t key;
+    int msgid;
+
+    // ftok to generate unique key
+    key = ftok("progfile", 65);
+
+    // msgget creates a message queue
+    // and returns identifier
+    msgid = msgget(key, 0666 | IPC_CREAT);
+
+    // msgrcv to receive message
+    msgrcv(msgid, &message, sizeof(message), 0, 0);
+    printf("Data Received is : %s \n", message.mesg_text);
+    msgrcv(msgid, &message, sizeof(message), 0, 0);
+    printf("Data Received is : %s \n", message.mesg_text);
+    msgrcv(msgid, &message, sizeof(message), 0, 0);
+    printf("Data Received is : %s \n", message.mesg_text);
+    msgrcv(msgid, &message, sizeof(message), 0, 0);
+    printf("Data Received is : %s \n", message.mesg_text);
+
+    // to destroy the message queue
+    msgctl(msgid, IPC_RMID, NULL);
+
+    return 0;
+}

Examples/ipc/ipcmsg_gfg_s.c

@@ -0,0 +1,46 @@
+// C Program for Message Queue (Writer Process)
+#include <stdio.h>
+#include <sys/ipc.h>
+#include <sys/msg.h>
+#define MAX 10
+
+// structure for message queue
+struct mesg_buffer
+{
+    long mesg_type;
+    char mesg_text[100];
+} m1, m2, m3, m4;
+
+int main()
+{
+    key_t key;
+    int msgid;
+
+    // ftok to generate unique key
+    key = ftok("progfile", 65);
+
+    // msgget creates a message queue
+    // and returns identifier
+    msgid = msgget(key, 0666 | IPC_CREAT);
+    m1.mesg_type = 1;
+    m2.mesg_type = 2;
+    m3.mesg_type = 3;
+    m4.mesg_type = 4;
+
+    printf("Write Data : ");
+    fgets(m1.mesg_text, MAX, stdin);
+    fgets(m2.mesg_text, MAX, stdin);
+    fgets(m3.mesg_text, MAX, stdin);
+    fgets(m4.mesg_text, MAX, stdin);
+
+    // msgsnd to send message
+    msgsnd(msgid, &m1, sizeof(m1), 0);
+    msgsnd(msgid, &m2, sizeof(m2), 0);
+    msgsnd(msgid, &m3, sizeof(m3), 0);
+    msgsnd(msgid, &m4, sizeof(m4), 0);
+
+    // display the message
+    // printf("Data send is : %s \n", message.mesg_text);
+
+    return 0;
+}

Examples/ipc/ipcsignal.c

@@ -3,12 +3,12 @@
  *               to send a signal from one process to another
  */
 
+#include <signal.h>    // needed for signal system call
+#include <stdio.h>     // needed for printf, perror
+#include <stdlib.h>    // needed for exit
 #include <sys/types.h> // needed for pid_t
 #include <sys/wait.h>  // needed for wait system call
 #include <unistd.h>    // needed for fork, getpid, getppid, kill system calls
-#include <stdlib.h>    // needed for exit
-#include <signal.h>    // needed for signal system call
-#include <stdio.h>     // needed for printf, perror
 
 void signal_handler(int sig)
 {
@@ -23,12 +23,12 @@ int main()
 
     pid_t pid = fork(); // fork into 2 processes
 
-    if(pid < 0) // error
+    if (pid < 0) // error
     {
         perror("fork");
         exit(EXIT_FAILURE);
     }
-    else if(pid == 0) // child
+    else if (pid == 0) // child
     {
         // Send a signal to the parent by its PID
         pid_t parent_pid = getppid();