notes/snippet/cpp/shm/map_normfile_read.c

25 lines
546 B
C

#include <sys/mman.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
typedef struct {
char name[4];
int age;
} people;
int main(int argc, char **argv) {
int fd, i;
people *p_map;
fd = open(argv[1], O_CREAT|O_RDWR, 00777);
p_map = (people *)mmap(NULL, sizeof(people)*10, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
for (i = 0; i < 10; i++) {
printf("name: %s, age: %d;\n", (*(p_map+i)).name, (*(p_map)).age);
}
munmap(p_map, sizeof(people)*10);
}