path: root / Year 3 / System programming / Practice10 / ex2-2.c


1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24

#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>

int main() {
	const char msg[] = "hello world";
	size_t msglen = strlen(msg) + 1;

	int shmd = shm_open("/shm", O_RDONLY, 0755);
	ftruncate(shmd, msglen);
	char* memory = mmap(NULL, msglen, PROT_READ, MAP_SHARED, shmd, 0);

	char buf[1024];
	strncpy(buf, memory, msglen);
	write(1, buf, msglen);

	munmap(memory, msglen);
	close(shmd);
	shm_unlink("/shm");
	return 0;
}