#include <time.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <stdio.h>
#include <stdio.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/errno.h>
#include <semaphore.h>

#define MMAP_SIZE 5000

void usage() {
	fprintf(stdout, "usage.....\n");
	fprintf(stdout, " shm_create object-file\n");
	fprintf(stdout, "ex) shm_create hoge\n");
	exit(0);
}

int main(int argc, char **argv) {
	int	fd;
	int ret;
	char *addr;
	int	i;
	char *walker;
	int fde, rete;
	char shm_object[1024];

	if (argc <= 1) usage();

	/* BSD = not "/" */
	/* sprintf(shm_object, "/%s", argv[1]); */
	sprintf(shm_object, "%s", argv[1]);

	fd = shm_open(shm_object, O_CREAT | O_RDWR, 0666);
	fde = errno;
	ret = ftruncate(fd, MMAP_SIZE);
	rete = errno;

	printf("fd = %d(%d), ret = %d(%d)\n", fd, fde, ret, rete );

	addr = mmap(0, MMAP_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
	if (addr == MAP_FAILED) {
		exit(1);
	}

	walker = (char *)addr;
	for (i = 0; i < MMAP_SIZE/sizeof(char); i++) {
		*walker = 'M';
		walker++;
	}
}