diff --git a/libc/include/utmp.h b/libc/include/utmp.h
index 6a52511..cb72ce2 100644
--- a/libc/include/utmp.h
+++ b/libc/include/utmp.h
@@ -25,8 +25,13 @@
  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
-#ifndef _UTMP_H_
-#define _UTMP_H_
+
+#pragma once
+
+/**
+ * @file utmp.h
+ * @brief POSIX login records.
+ */
 
 #include <sys/cdefs.h>
 #include <sys/types.h>
@@ -57,52 +62,71 @@
 #define DEAD_PROCESS  8
 #define ACCOUNTING    9
 
-struct lastlog
-{
-    time_t ll_time;
-    char ll_line[UT_LINESIZE];
-    char ll_host[UT_HOSTSIZE];
+struct lastlog {
+  time_t ll_time;
+  char ll_line[UT_LINESIZE];
+  char ll_host[UT_HOSTSIZE];
 };
 
-struct exit_status
-{
-    short int e_termination;
-    short int e_exit;
+struct exit_status {
+  short int e_termination;
+  short int e_exit;
 };
 
+struct utmp {
+  short int ut_type;
+  pid_t ut_pid;
+  char ut_line[UT_LINESIZE];
+  char ut_id[4];
+  char ut_user[UT_NAMESIZE];
+  char ut_host[UT_HOSTSIZE];
 
-struct utmp
-{
-    short int ut_type;
-    pid_t ut_pid;
-    char ut_line[UT_LINESIZE];
-    char ut_id[4];
-    char ut_user[UT_NAMESIZE];
-    char ut_host[UT_HOSTSIZE];
+  struct exit_status ut_exit;
 
-    struct exit_status ut_exit;
+  long int ut_session;
+  struct timeval ut_tv;
 
-    long int ut_session;
-    struct timeval ut_tv;
-
-    int32_t ut_addr_v6[4];
-    char unsed[20];
+  int32_t ut_addr_v6[4];
+  char unused[20];
 };
 
-
 #define ut_name ut_user
 #define ut_time ut_tv.tv_sec
 #define ut_addr ut_addr_v6[0]
 
 __BEGIN_DECLS
 
+/**
+ * Does nothing.
+ */
 int utmpname(const char* __path);
+/**
+ * Does nothing.
+ */
 void setutent(void);
+/**
+ * Does nothing.
+ */
 struct utmp* getutent(void);
+/**
+ * Does nothing.
+ */
+struct utmp* pututline(const struct utmp* __entry);
+/**
+ * Does nothing.
+ */
 void endutent(void);
 
+/**
+ * [login_tty(3)](https://www.man7.org/linux/man-pages/man3/login_tty.3.html)
+ * prepares for login on the given file descriptor.
+ *
+ * See also forkpty() which combines openpty(), fork(), and login_tty().
+ *
+ * Returns 0 on success and returns -1 and sets `errno` on failure.
+ *
+ * Available since API level 23.
+ */
 int login_tty(int __fd) __INTRODUCED_IN(23);
 
 __END_DECLS
-
-#endif /* _UTMP_H_ */