map_seq.c

/*******************************************
* Author     : Diego Cordoba / @d1cor      *
* Purpose    : juncotic.com  / um.edu.ar   *
*******************************************/

#include<stdio.h>
#include<stdio.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<unistd.h>
#include<dirent.h>
#include<fcntl.h>
#include<errno.h>
#include<sys/mman.h>
#include<string.h>

#define MIN_SIZE 128

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

    int fd,i=0;
    char *buffer;
    struct stat estado;
    fd=open("/tmp/archivo.txt",O_RDWR|O_CREAT,0777);
    printf("%s\n",strerror(errno));



    fstat(fd,&estado);

    if(estado.st_size < MIN_SIZE){
        ftruncate(fd,MIN_SIZE);
    }

    printf("Tamanio: %d\n",estado.st_size);

    if((buffer=mmap(NULL, MIN_SIZE, PROT_WRITE, MAP_SHARED, fd, 0))<0){
        close(fd);
        perror("Error de mapeo");
        printf("%s\n",strerror(errno));
        exit(EXIT_FAILURE);
    }


    for(i=0;i<15;i++){
        *(buffer+i)=*argv[1];
        msync(buffer,estado.st_size,MS_ASYNC);
        printf("%s\n",strerror(errno));
        sleep(1);
    }

    munmap(buffer,MIN_SIZE);

    return 0;
}

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