Creating, writing to and reading from shared memory program

This is an operating systems program to implement creating, writing to and reading from a shared memory. If you have any doubts please let me know.

#include<sys/mman.h>                                                                                                                                                                                                                           

#include<sys/stat.h>

#include<fcntl.h>

#include<stdio.h>

main()

{

    int fd;

    char mamname[20];

    printf(“\nEnter the shared memory name: “);

   scanf(“%s”,memname);

   fd=shm_open(memname,O_CREAT,S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);

   ftruncate(fd,100);

   if(fd>0)

   printf(“\nSUCCESS”);

   else

   printf(“\nFAIL”);

}

#include<sys/mman.h>                                                                                                                                                                                                                            

#include<sys/stat.h>

#include<fcntl.h>

#include<stdio.h>

main()

{

    int fd,i;

    char mamname[20];

    unsigned char *ptr;

    printf(“\nEnter the shared memory name: “);

   scanf(“%s”,memname);

   fd=shm_open(memname,O_CREAT,S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);

   ptr=mmap(NULL,100,PROT_READ|PROT_WRITE,MAP_SHARED,fd,0);

   for(i=0;*(ptr+i)!=’\0’;i++)

    printf(“%c”,*(ptr+i));

}

#include<sys/mman.h>                                                                                                                                                                                                                            

#include<sys/stat.h>

#include<fcntl.h>

#include<stdio.h>

main()

{

    int fd,i;

    char mamname[20],s[100];

    unsigned char *ptr;

    printf(“\nEnter the shared memory name: “);

   scanf(“%s”,memname);

   fd=shm_open(memname,O_CREAT,S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH);

   ptr=mmap(NULL,100,PROT_READ|PROT_WRITE,MAP_SHARED,fd,0);

   if(fd>0)

   {

    printf(“\nEnter data:”);

   gets(s);

   for(i=0;s[i]!=’\0’;i++)

    *(ptr+i)=s[i];

}