int read_and_compare(int fd, const char *expectation);
int xwrite(int fd, const char *buf, size_t len);
int xwritev(int fd, struct iovec *iov, int iovcnt);
-int for_each_file_in_dir(const char *dirname,
- int (*func)(const char *, void *), void *private_data);
+
/**
* Write a \p NULL-terminated buffer.
*