fd=open("/tmp/nonexistant","r");
printf("nonexistant file opened for reading: %a (should be nil)\n",fd);

fd=open("/tmp/nonexistant","r+");
printf("nonexistant file opened for reading and writing: %a (should be nil)\n",fd);

unlink("/tmp/willexist");

r=unlink("/tmp/willexist");
printf("unlink: %a (should fail)\n",r);

fd=open("/tmp/willexist","r");
printf("(hopefully) nonexistant file opened for reading: %a (should be nil)\n",fd);

fd=open("/tmp/willexist","w");
printf("(hopefully) nonexistant file opened for writing: %a (should succeed)\n",fd);

contents="Schaefer is the one beer to have when you're having more than one";
write(fd,contents);

printf("(hopefully) wrote %d bytes\n",strlen(contents));

close(fd);

s=mapfile("/tmp/willexist");
printf("length of empty file: %d\n",length(s));
s=nil;

r=unlink("/tmp/willexist");
printf("unlink: %a (should succeed)\n",r);

fd=open("/tmp/willexist","r");
printf("(hopefully) nonexistent file re-opened for reading: %a (should be nil)\n",fd);

gc(3,3);