setpwent(3)

1GETPWENT(3)                Linux Programmer's Manual               GETPWENT(3)
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NAME

6       getpwent, setpwent, endpwent - get password file entry
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SYNOPSIS

9       #include <sys/types.h>
10       #include <pwd.h>
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12       struct passwd *getpwent(void);
13       void setpwent(void);
14       void endpwent(void);
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16   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
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18       getpwent(), setpwent(), endpwent():
19           _XOPEN_SOURCE >= 500
20               || /* Glibc since 2.19: */ _DEFAULT_SOURCE
21               || /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
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DESCRIPTION

24       The getpwent() function returns a pointer to a structure containing the
25       broken-out fields of a record from the password database (e.g., the lo‐
26       cal  password  file  /etc/passwd, NIS, and LDAP).  The first time getp‐
27       went() is called, it returns the first entry;  thereafter,  it  returns
28       successive entries.
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30       The  setpwent() function rewinds to the beginning of the password data‐
31       base.
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33       The endpwent() function is used to close the  password  database  after
34       all processing has been performed.
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36       The passwd structure is defined in <pwd.h> as follows:
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38           struct passwd {
39               char   *pw_name;       /* username */
40               char   *pw_passwd;     /* user password */
41               uid_t   pw_uid;        /* user ID */
42               gid_t   pw_gid;        /* group ID */
43               char   *pw_gecos;      /* user information */
44               char   *pw_dir;        /* home directory */
45               char   *pw_shell;      /* shell program */
46           };
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48       For more information about the fields of this structure, see passwd(5).
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RETURN VALUE

51       The  getpwent()  function  returns  a pointer to a passwd structure, or
52       NULL if there are no more entries or an error occurred.   If  an  error
53       occurs,  errno is set to indicate the error.  If one wants to check er‐
54       rno after the call, it should be set to zero before the call.
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56       The return value may point to a static area, and may be overwritten  by
57       subsequent  calls  to getpwent(), getpwnam(3), or getpwuid(3).  (Do not
58       pass the returned pointer to free(3).)
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ERRORS

61       EINTR  A signal was caught; see signal(7).
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63       EIO    I/O error.
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65       EMFILE The per-process limit on the number of open file descriptors has
66              been reached.
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68       ENFILE The system-wide limit on the total number of open files has been
69              reached.
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71       ENOMEM Insufficient memory to allocate passwd structure.
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73       ERANGE Insufficient buffer space supplied.
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FILES

76       /etc/passwd
77              local password database file
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ATTRIBUTES

80       For an  explanation  of  the  terms  used  in  this  section,  see  at‐
81       tributes(7).
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83       ┌────────────┬───────────────┬─────────────────────────────────────────┐
84       │Interface   │ Attribute     │ Value                                   │
85       ├────────────┼───────────────┼─────────────────────────────────────────┤
86       │getpwent()  │ Thread safety │ MT-Unsafe race:pwent race:pwentbuf      │
87       │            │               │ locale                                  │
88       ├────────────┼───────────────┼─────────────────────────────────────────┤
89       │setpwent(), │ Thread safety │ MT-Unsafe race:pwent locale             │
90       │endpwent()  │               │                                         │
91       └────────────┴───────────────┴─────────────────────────────────────────┘
92       In  the  above  table, pwent in race:pwent signifies that if any of the
93       functions setpwent(), getpwent(), or endpwent() are used in parallel in
94       different threads of a program, then data races could occur.
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CONFORMING TO

97       POSIX.1-2001,  POSIX.1-2008,  SVr4,  4.3BSD.  The pw_gecos field is not
98       specified in POSIX, but is present on most implementations.
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COLOPHON

105       This  page  is  part of release 5.13 of the Linux man-pages project.  A
106       description of the project, information about reporting bugs,  and  the
107       latest     version     of     this    page,    can    be    found    at
108       https://www.kernel.org/doc/man-pages/.
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112GNU                               2021-03-22                       GETPWENT(3)