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Trailing-Edge - PDP-10 Archives - SRI_NIC_PERM_FS_1_19910112 - c/old/include/utmp.h
There are no other files named utmp.h in the archive.
/*	utmp.h	4.2	83/05/22	*/

/*
 * Structure of utmp and wtmp files.
 *
 * Assuming the number 8 is unwise.
 */
struct utmp {
	char	ut_line[8];		/* tty name */
	char	ut_name[8];		/* user id */
	char	ut_host[16];		/* host name, if remote */
	long	ut_time;		/* time on */
};