POSIX: producer-consumer using shared memory

Author: dalmia

3-Process Concept/a.out

@@ -0,0 +1,32 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/shm.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+
+int main()
+{
+/* size (in bytes) of shared memory object */
+const int SIZE = 4096;
+/* name of the shared memory object */
+const char *name = "OS";
+/* shared memory file descriptor */
+int shm_fd;
+/* pointer to shared memory object */
+void *ptr;
+
+ /* open the shared memory object */
+ shm_fd = shm_open(name, O_RDONLY, 0666);
+
+ /* memory map the shared memory object */
+ ptr = mmap(0, SIZE, PROT_READ, MAP_SHARED, shm_fd, 0);
+
+ /* read from the shared memory object */
+ printf("%s\n", (char *)ptr);
+
+ /* remove the shared memory object */
+ shm_unlink(name);
+
+ return 0;
+}

3-Process Concept/consumer

@@ -2,4 +2,38 @@
 #include <stdlib.h>
 #include <string.h>
 #include <fcntl.h>
-#include <sys/shm.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+
+int main()
+{
+/* size (in bytes) of shared memory object */
+const int SIZE = 4096;
+/* name of the shared memory object */
+const char *name = "OS";
+/* strings written to shared memory */
+const char *message_0 = "Hello";
+const char *message_1 = "World";
+
+/* shared memory file descriptor */
+int shm_fd;
+/* pointer to shared memory object */
+void *ptr;
+
+ /* create the shared memory object */
+ shm_fd = shm_open(name, O_CREAT | O_RDWR, 0666);
+
+ /* configure the size of the shared memory object */
+ ftruncate(shm_fd, SIZE);
+
+ /* memory map the shared memory object */
+ ptr = mmap(0, SIZE, PROT_WRITE, MAP_SHARED, shm_fd, 0);
+
+ /* write to the shared memory object */
+ sprintf(ptr, "%s", message_0);
+ ptr += strlen(message_0);
+ sprintf(ptr, "%s", message_1);
+ ptr += strlen(message_1);
+
+ return 0;
+}