1GETUTENT(3)                    Library functions                   GETUTENT(3)
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NAME

6       getutent, getutid, getutline, pututline, setutent, endutent, utmpname -
7       access utmp file entries
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SYNOPSIS

10       #include <utmp.h>
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12       struct utmp *getutent(void);
13       struct utmp *getutid(struct utmp *ut);
14       struct utmp *getutline(struct utmp *ut);
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16       struct utmp *pututline(struct utmp *ut);
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18       void setutent(void);
19       void endutent(void);
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21       void utmpname(const char *file);
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DESCRIPTION

24       utmpname() sets the name of the utmp-format file  for  the  other  utmp
25       functions  to  access.   If  utmpname() is not used to set the filename
26       before the other functions are used, they assume _PATH_UTMP, as defined
27       in <paths.h>.
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29       setutent()  rewinds the file pointer to the beginning of the utmp file.
30       It is generally a Good Idea to call it before any of  the  other  func‐
31       tions.
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33       endutent()  closes  the  utmp  file.  It should be called when the user
34       code is done accessing the file with the other functions.
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36       getutent() reads a line from the current  file  position  in  the  utmp
37       file.  It returns a pointer to a structure containing the fields of the
38       line.
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40       getutid() searches forward from the current file position in  the  utmp
41       file  based  upon  ut.   If  ut->ut_type  is one of RUN_LVL, BOOT_TIME,
42       NEW_TIME, or OLD_TIME,  getutid()  will  find  the  first  entry  whose
43       ut_type   field   matches   ut->ut_type.   If  ut->ut_type  is  one  of
44       INIT_PROCESS, LOGIN_PROCESS, USER_PROCESS, or  DEAD_PROCESS,  getutid()
45       will find the first entry whose ut_id field matches ut->ut_id.
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47       getutline() searches forward from the current file position in the utmp
48       file.  It scans entries whose ut_type is USER_PROCESS or  LOGIN_PROCESS
49       and returns the first one whose ut_line field matches ut->ut_line.
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51       pututline()  writes  the utmp structure ut into the utmp file.  It uses
52       getutid() to search for the proper place in the file to insert the  new
53       entry.   If it cannot find an appropriate slot for ut, pututline() will
54       append the new entry to the end of the file.
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RETURN VALUE

57       getutent(), getutid(), getutline() and pututline() return a pointer  to
58       a  struct  utmp  on  success, and NULL on failure.  This struct utmp is
59       allocated in static storage,  and  may  be  overwritten  by  subsequent
60       calls.
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REENTRANT VERSIONS

63       These  above  functions  are not thread-safe. Glibc adds reentrant ver‐
64       sions
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66       #define _GNU_SOURCE    /* or _SVID_SOURCE or _BSD_SOURCE */
67       #include <utmp.h>
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69       int getutent_r(struct utmp *ubuf, struct utmp **ubufp);
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71       int getutid_r(struct utmp *ut,
72                     struct utmp *ubuf, struct utmp **ubufp);
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74       int getutline_r(struct utmp *ut,
75                       struct utmp *ubuf, struct utmp **ubufp);
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77       These functions are GNU extensions, analogs of  the  functions  of  the
78       same  name  without the _r suffix. The ubuf parameter gives these func‐
79       tions a place to store their result.  On success