- * \return A dynamically allocated string that must be freed by the caller. If
- * the home directory could not be found, this function returns "/tmp".
+ * If the environment variable HOME is unset or empty, the function prints an
+ * error message and aborts. Otherwise, on the first call the memory for the
+ * string is allocated and a pointer to this memory location is returned.
+ * Subsequent calls return a pointer to the memory that was allocated during
+ * the first call.
+ *
+ * \return A pointer to a C string, allocated on the heap. Callers should make
+ * sure that free() is only called once.
+ *
+ * \sa getenv(3), getuid(2).