updwtmp, logwtmp - append an entry to the wtmp file
System utilities library (libutil, -lutil)
#include <utmp.h>
void updwtmp(const char *wtmp_file, const struct utmp *ut);
void logwtmp(const char *line, const char *name, const char *host);
updwtmp() appends the utmp structure ut to the wtmp file.
logwtmp() constructs a utmp structure using line, name, host, current time, and current process ID. Then it calls updwtmp() to append the structure to the wtmp file.
- /var/log/wtmp
- database of past user logins
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
| updwtmp (), logwtmp () | Thread safety | MT-Unsafe sig:ALRM timer |
For consistency with the other "utmpx" functions (see getutxent(3)), glibc provides (since glibc 2.1):
#define _GNU_SOURCE /* See feature_test_macros(7) */
#include <utmpx.h>
void updwtmpx (const char *wtmpx_file, const struct utmpx *utx);
This function performs the same task as updwtmp(), but differs in that it takes a utmpx structure as its last argument.