share memory

header for public argument：shmdata.h

#define TEXT_SZ 2048
 
struct shared_use_st
 
{
 
        int written;
 
        char text[TEXT_SZ];
 
};
 
#endif

shmread.c

#include <unistd.h>
 
#include <stdlib.h>
 
#include <stdio.h>
 
#include <sys/shm.h>
 
#include "shmdata.h"
 
int main()
 
{
 
        int running = ;
 
        void *shm = NULL;
 
        struct shared_use_st *shared;
 
        int shmid;  
 
       shmid = shmget((key_t), sizeof(struct shared_use_st), |IPC_CREAT);
 
        if(shmid == -)
 
        {
 
                fprintf(stderr, "shmget failed\n");
 
                exit(EXIT_FAILURE);
 
        }
 
        shm = shmat(shmid, , );
 
        if(shm == (void*)-)
 
        {  
 
               fprintf(stderr, "shmat failed\n");
 
                exit(EXIT_FAILURE);
 
        }  
 
       shared = (struct shared_use_st*)shm;
 
        shared->written = ;  
 
       while(running)
 
        {     
 
            if(shared->written != )
 
           {  
 
                       printf("You wrote: %s", shared->text);
 
                        sleep(rand() % );
 
                        shared->written = ;  
 
                       if(strncmp(shared->text, "end", ) == )
 
                                running = ;
 
            }    
 
             else
 
                        sleep();
 
        }
 
        if(shmdt(shm) == -)
 
        {
 
                fprintf(stderr, "shmdt failed\n");
 
                exit(EXIT_FAILURE);
 
        }
 
        if(shmctl(shmid, IPC_RMID, ) == -)
 
        {
                fprintf(stderr, "shmctl(IPC_RMID) failed\n");
                exit(EXIT_FAILURE);
        }
        exit(EXIT_SUCCESS);
}

shmwrite.c

#include <unistd.h>
 
#include <stdlib.h>
 
#include <stdio.h>
 
#include <string.h>
 
#include <sys/shm.h>
 
#include "shmdata.h"
 
int main()
 
{
 
        int running = ;
 
        void *shm = NULL;
 
        struct shared_use_st *shared = NULL;   
 
      char buffer[BUFSIZ + ];  
 
       int shmid;  
 
       shmid = shmget((key_t), sizeof(struct shared_use_st), |IPC_CREAT);
 
        if(shmid == -)
 
        {
 
                fprintf(stderr, "shmget failed\n");
 
                exit(EXIT_FAILURE);
 
        }  
 
       shm = shmat(shmid, (void*), );
 
        if(shm == (void*)-)
 
        {
 
                fprintf(stderr, "shmat failed\n");
 
                exit(EXIT_FAILURE);
 
        }
 
        shared = (struct shared_use_st*)shm;
 
        while(running)
 
　　{
 
                while(shared->written == )
 
                {
 
                        sleep();
 
                        printf("Waiting...\n");
 
                }
 
                printf("Enter some text: ");
 
                fgets(buffer, BUFSIZ, stdin);
 
                strncpy(shared->text, buffer, TEXT_SZ);
 
                shared->written = ;
 
                if(strncmp(buffer, "end", ) == )
 
                        running = ;
 
        }   
 
      if(shmdt(shm) == -)
 
        {  
 
               fprintf(stderr, "shmdt failed\n");
 
                exit(EXIT_FAILURE);
 
        }
 
        sleep();
        exit(EXIT_SUCCESS);
}