#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);

	int shmd = shm_open("/shm", O_RDWR | O_CREAT | O_TRUNC, 0755);
	ftruncate(shmd, msglen);
	char* memory = mmap(NULL, msglen, PROT_WRITE, MAP_SHARED, shmd, 0);

	strncpy(memory, msg, msglen);

	munmap(memory, msglen);
	close(shmd);
	return 0;
}