#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main (void)
{
	char *buf;
	char  buf2[512];
	FILE *fp;
	int   rc;

	if ((buf = malloc (1024 * 1024)) == NULL) {
		puts ("Cannot allocate");
		return 1;
	}

	if ((fp = fmemopen (buf2, sizeof buf2, "w")) == NULL) {
		puts ("Cannot fmemopen");
	}
	setvbuf (fp, (char *) NULL, _IONBF, 0);

	if ((rc = fwrite (buf, 1, 1024*1024, fp)) != 1024*1024) {
		printf ("Got %d\n", rc);
	}

	fclose (fp);
	free   (buf);

	return 0;
}