ENDUTXENT(3)               POSIX Programmer's Manual              ENDUTXENT(3)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NAME
       endutxent, getutxent, getutxid, getutxline, pututxline, setutxent --
       user accounting database functions

SYNOPSIS
       #include <utmpx.h>

       void endutxent(void);
       struct utmpx *getutxent(void);
       struct utmpx *getutxid(const struct utmpx *id);
       struct utmpx *getutxline(const struct utmpx *line);
       struct utmpx *pututxline(const struct utmpx *utmpx);
       void setutxent(void);

DESCRIPTION
       These functions shall provide access to the user accounting database.

       The getutxent() function shall read the next entry from the user
       accounting database.  If the database is not already open, it shall
       open it. If it reaches the end of the database, it shall fail.

       The getutxid() function shall search forward from the current point in
       the database.  If the ut__type value of the utmpx structure pointed to
       by id is BOOT_TIME, OLD_TIME, or NEW_TIME, then it shall stop when it
       finds an entry with a matching ut__type value. If the ut__type value is
       INIT_PROCESS, LOGIN_PROCESS, USER_PROCESS, or DEAD_PROCESS, then it
       shall stop when it finds an entry whose type is one of these four and
       whose ut__id member matches the ut__id member of the utmpx structure
       pointed to by id.  If the end of the database is reached without a
       match, getutxid() shall fail.

       The getutxline() function shall search forward from the current point
       in the database until it finds an entry of the type LOGIN_PROCESS or
       USER_PROCESS which also has a ut__line value matching that in the utmpx
       structure pointed to by line.  If the end of the database is reached
       without a match, getutxline() shall fail.

       The getutxid() or getutxline() function may cache data. For this
       reason, to use getutxline() to search for multiple occurrences, the
       application shall zero out the static data after each success, or
       getutxline() may return a pointer to the same utmpx structure.

       There is one exception to the rule about clearing the structure before
       further reads are done. The implicit read done by pututxline() (if it
       finds that it is not already at the correct place in the user
       accounting database) shall not modify the static structure returned by
       getutxent(), getutxid(), or getutxline(), if the application has
       modified this structure and passed the pointer back to pututxline().

       For all entries that match a request, the ut__type member indicates the
       type of the entry. Other members of the entry shall contain meaningful
       data based on the value of the ut__type member as follows:

  +---------------+-----------------------------------------------------------------+
  |ut_type Member |               Other Members with Meaningful Data                |
  +---------------+-----------------------------------------------------------------+
  |EMPTY          | No others                                                       |
  |BOOT_TIME      | ut__tv                                                           |
  |OLD_TIME       | ut__tv                                                           |
  |NEW_TIME       | ut__tv                                                           |
  |USER_PROCESS   | ut__id, ut__user (login name of the user), ut__line, ut__pid, ut__tv |
  |INIT_PROCESS   | ut__id, ut__pid, ut__tv                                            |
  |LOGIN_PROCESS  | ut__id, ut__user (implementation-defined name of the login        |
  |               | process), ut__line, ut__pid, ut__tv                                |
  |DEAD_PROCESS   | ut__id, ut__pid, ut__tv                                            |
  +---------------+-----------------------------------------------------------------+
       An implementation that provides extended security controls may impose
       implementation-defined restrictions on accessing the user accounting
       database. In particular, the system may deny the existence of some or
       all of the user accounting database entries associated with users other
       than the caller.

       If the process has appropriate privileges, the pututxline() function
       shall write out the structure into the user accounting database. It
       shall search for a record as if by getutxid() that satisfies the
       request. If this search succeeds, then the entry shall be replaced.
       Otherwise, a new entry shall be made at the end of the user accounting
       database.

       The endutxent() function shall close the user accounting database.

       The setutxent() function shall reset the input to the beginning of the
       database. This should be done before each search for a new entry if it
       is desired that the entire database be examined.

       These functions need not be thread-safe.

RETURN VALUE
       Upon successful completion, getutxent(), getutxid(), and getutxline()
       shall return a pointer to a utmpx structure containing a copy of the
       requested entry in the user accounting database. Otherwise, a null
       pointer shall be returned.

       The return value may point to a static area which is overwritten by a
       subsequent call to getutxid() or getutxline().

       Upon successful completion, pututxline() shall return a pointer to a
       utmpx structure containing a copy of the entry added to the user
       accounting database. Otherwise, a null pointer shall be returned.

       The endutxent() and setutxent() functions shall not return a value.

ERRORS
       No errors are defined for the endutxent(), getutxent(), getutxid(),
       getutxline(), and setutxent() functions.

       The pututxline() function may fail if:

       EPERM  The process does not have appropriate privileges.

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       The sizes of the arrays in the structure can be found using the sizeof
       operator.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       The Base Definitions volume of POSIX.1-2017, <utmpx.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  In the event of any discrepancy between this version and the
       original IEEE and The Open Group Standard, the original IEEE and The
       Open Group Standard is the referee document. The original Standard can
       be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                         ENDUTXENT(3)
