#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/shm.h>
#include <sys/stat.h>

#include <sys/mman.h>
#include <unistd.h>

using namespace std;

const int SIZE{4096};

// look at /dev/shm
const string NAME{"/SharedMem"};

int main( int argc, char * argv[]) {

    if (argc < 2) {
       cerr << "Usage " << argv[0] << " arg1 arg2 ..." << endl;
       return 0;
    }

    int openFlags {O_CREAT | O_RDWR | O_TRUNC};
    mode_t mode{ S_IRUSR | S_IWUSR};
    int fd{shm_open(NAME.c_str(), openFlags, mode)};

    if (fd == -1) {
       perror("\tError shm_open: ");
       return 1;
    }

    if( -1 == ftruncate(fd, SIZE)) {
       perror("\tError ftruncate: ");
       shm_unlink(NAME.c_str());
       return 1;
    }

    int protect{ PROT_READ| PROT_WRITE};
    char* basePtr = reinterpret_cast<char *> (
                 mmap(0, SIZE, protect, MAP_SHARED, fd, 0));
    close(fd);

    if(basePtr == MAP_FAILED) {
        perror("\tError mmap: ");
    }  else {
        for(int i = 1; i < argc; ++i) {
            sprintf(basePtr, "%s ", argv[i]);
            basePtr += strlen(argv[i]) + 1;
        }
    }
   
    return 0;
    
}