Übung 5

Assets/Betriebssysteme_uebung/u2-anlage/u2-a1-anlage/Makefile

@@ -0,0 +1,16 @@
+all: p1 p2 p3 p4
+
+p1:
+	cc -o p1 p1.c
+
+p2:
+	cc -o p2 p2.c
+
+p3:
+	cc -o p3 p3.c
+
+p4:
+	cc -o p4 p4.c
+
+clean:
+	rm -f p1 p2 p3 p4

Assets/Betriebssysteme_uebung/u2-anlage/u2-a1-anlage/p1.c

@@ -0,0 +1,11 @@
+#include <stdio.h>
+#include <unistd.h>
+
+int main()
+{
+  printf("%d: code before forking - executed once only\n", getpid());
+
+  fork();
+
+  printf("%d: code after forking - executed by each process\n", getpid());
+}

Assets/Betriebssysteme_uebung/u2-anlage/u2-a1-anlage/p2.c

@@ -0,0 +1,20 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+int main()
+{
+  if (fork() == 0)
+  { // child proc
+    printf("%d: child created by parent %d; executing 'p4'...\n", getpid(), getppid());
+    execl("p4", "p4", NULL);
+    printf("system call execl(): no success\n");
+  }
+  else
+  { // parent proc
+    printf("%d: parent process\n", getpid());
+  }
+
+  wait(NULL);
+}

Assets/Betriebssysteme_uebung/u2-anlage/u2-a1-anlage/p3.c

@@ -0,0 +1,22 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+
+int main()
+{
+  if (fork() == 0)
+  { // child proc
+    printf("%d: child created by parent %d; executing 'p4'...\n", getpid(), getppid());
+    execl("p4", "p4", NULL);
+  }
+  else
+  { // parent proc
+    printf("%d: parent process\n", getpid());
+  }
+
+  fork();
+  printf("%d: terminating\n", getpid());
+
+  wait(NULL);
+}

Assets/Betriebssysteme_uebung/u2-anlage/u2-a1-anlage/p4.c

@@ -0,0 +1,7 @@
+#include <stdio.h>
+#include <unistd.h>
+
+int main()
+{
+  printf("%d: p4 running\n", getpid());
+}