c/mmap/mmap.c

   1 //#define _GNU_SOURCE
   2
   3 #include <stdio.h>
   4 #include <sys/types.h>
   5 #include <sys/stat.h>
   6 #include <sys/mman.h>
   7 #include <fcntl.h>
   8 #include <unistd.h>
   9 #include <string.h>
  10
  11 #define MEM_PATH "hello.bin"
  12 #define MEM_SIZE 1048576
  13
  14 int main() {
  15         int fd;
  16         fd = open(MEM_PATH, O_RDWR | O_SYNC | O_CREAT | O_CLOEXEC, S_IRUSR | S_IWUSR);
  17         ftruncate(fd, MEM_SIZE);
  18
  19         void *mem;
  20         mem = mmap(NULL, MEM_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED , fd, 0);
  21         close(fd);
  22
  23         char hello[] = "Hello!";
  24         memcpy(mem, hello, sizeof(hello));
  25         msync(mem, sizeof(hello), MS_SYNC);
  26 }