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);
}