1GETPWENT(3) Linux Programmer's Manual GETPWENT(3)
2
6 getpwent, setpwent, endpwent - get password file entry
7
9 #include <sys/types.h>
10 #include <pwd.h>
11 struct passwd *getpwent(void);
13 void setpwent(void);
15 void endpwent(void);
17 Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
19 getpwent(), setpwent(), endpwent():
21 _XOPEN_SOURCE >= 500
22 || /* Glibc since 2.19: */ _DEFAULT_SOURCE
23 || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
24
26 The getpwent() function returns a pointer to a structure containing the
27 broken-out fields of a record from the password database (e.g., the
28 local password file /etc/passwd, NIS, and LDAP). The first time getp‐
29 went() is called, it returns the first entry; thereafter, it returns
30 successive entries.
31 The setpwent() function rewinds to the beginning of the password data‐
33 base.
34 The endpwent() function is used to close the password database after
36 all processing has been performed.
37 The passwd structure is defined in <pwd.h> as follows:
39 struct passwd {
41 char *pw_name; /* username */
42 char *pw_passwd; /* user password */
43 uid_t pw_uid; /* user ID */
44 gid_t pw_gid; /* group ID */
45 char *pw_gecos; /* user information */
46 char *pw_dir; /* home directory */
47 char *pw_shell; /* shell program */
48 };
49 For more information about the fields of this structure, see passwd(5).
51
53 The getpwent() function returns a pointer to a passwd structure, or
54 NULL if there are no more entries or an error occurred. If an error
55 occurs, errno is set appropriately. If one wants to check errno after
56 the call, it should be set to zero before the call.
57 The return value may point to a static area, and may be overwritten by
59 subsequent calls to getpwent(), getpwnam(3), or getpwuid(3). (Do not
60 pass the returned pointer to free(3).)
61
63 EINTR A signal was caught; see signal(7).
64 EIO I/O error.
66 EMFILE The per-process limit on the number of open file descriptors has
68 been reached.
69 ENFILE The system-wide limit on the total number of open files has been
71 reached.
72 ENOMEM Insufficient memory to allocate passwd structure.
74 ERANGE Insufficient buffer space supplied.
76
78 /etc/passwd
79 local password database file
80
82 For an explanation of the terms used in this section, see
83 attributes(7).
84 ┌────────────┬───────────────┬─────────────────────────────┐
86 │Interface │ Attribute │ Value │
87 ├────────────┼───────────────┼─────────────────────────────┤
88 │getpwent() │ Thread safety │ MT-Unsafe race:pwent │
89 │ │ │ race:pwentbuf locale │
90 ├────────────┼───────────────┼─────────────────────────────┤
91 │setpwent(), │ Thread safety │ MT-Unsafe race:pwent locale │
92 │endpwent() │ │ │
93 └────────────┴───────────────┴─────────────────────────────┘
94 In the above table, pwent in race:pwent signifies that if any of the
95 functions setpwent(), getpwent(), or endpwent() are used in parallel in
96 different threads of a program, then data races could occur.
97
99 POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD. The pw_gecos field is not
100 specified in POSIX, but is present on most implementations.
101
103 fgetpwent(3), getpw(3), getpwent_r(3), getpwnam(3), getpwuid(3), putp‐
104 went(3), passwd(5)
105
107 This page is part of release 4.16 of the Linux man-pages project. A
108 description of the project, information about reporting bugs, and the
109 latest version of this page, can be found at
110 https://www.kernel.org/doc/man-pages/.
111GNU 2017-09-15 GETPWENT(3)