1GETPWENT(3) Library Functions Manual GETPWENT(3)
2
6 getpwent, getpwuid, getpwnam, setpwent, endpwent - get password file
7 entry
8
10 #include <pwd.h>
11 struct passwd *getpwent();
13 struct passwd *getpwuid(uid) int uid;
15 struct passwd *getpwnam(name) char *name;
17 int setpwent();
19 int endpwent();
21
23 Getpwent, getpwuid and getpwnam each return a pointer to an object with
24 the following structure containing the broken-out fields of a line in
25 the password file.
26 /* Copyright (C) 1991,1992,1995-2001,2003,2004,2012
28 Free Software Foundation, Inc.
29 This file is part of the GNU C Library.
30 The GNU C Library is free software; you can redistribute it and/or
32 modify it under the terms of the GNU Lesser General Public
33 License as published by the Free Software Foundation; either
34 version 2.1 of the License, or (at your option) any later version.
35 The GNU C Library is distributed in the hope that it will be useful,
37 but WITHOUT ANY WARRANTY; without even the implied warranty of
38 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
39 Lesser General Public License for more details.
40 You should have received a copy of the GNU Lesser General Public
42 License along with the GNU C Library; if not, see
43 <http://www.gnu.org/licenses/>. */
44 /*
46 * POSIX Standard: 9.2.2 User Database Access <pwd.h>
47 */
48 #ifndef _PWD_H
50 #define _PWD_H 1
51 #include <features.h>
53 __BEGIN_DECLS
55 #include <bits/types.h>
57 #define __need_size_t
59 #include <stddef.h>
60 #if defined __USE_XOPEN || defined __USE_XOPEN2K
62 /* The Single Unix specification says that some more types are
63 available here. */
64 # ifndef __gid_t_defined
65 typedef __gid_t gid_t;
66 # define __gid_t_defined
67 # endif
68 # ifndef __uid_t_defined
70 typedef __uid_t uid_t;
71 # define __uid_t_defined
72 # endif
73 #endif
74 /* The passwd structure. */
76 struct passwd
77 {
78 char *pw_name; /* Username. */
79 char *pw_passwd; /* Password. */
80 __uid_t pw_uid; /* User ID. */
81 __gid_t pw_gid; /* Group ID. */
82 char *pw_gecos; /* Real name. */
83 char *pw_dir; /* Home directory. */
84 char *pw_shell; /* Shell program. */
85 };
86 #if defined __USE_SVID || defined __USE_GNU
89 # define __need_FILE
90 # include <stdio.h>
91 #endif
92 #if defined __USE_SVID || defined __USE_MISC || defined __USE_XOPEN_EXTENDED
95 /* Rewind the password-file stream.
96 This function is a possible cancellation point and therefore not
98 marked with __THROW. */
99 extern void setpwent (void);
100 /* Close the password-file stream.
102 This function is a possible cancellation point and therefore not
104 marked with __THROW. */
105 extern void endpwent (void);
106 /* Read an entry from the password-file stream, opening it if necessary.
108 This function is a possible cancellation point and therefore not
110 marked with __THROW. */
111 extern struct passwd *getpwent (void);
112 #endif
113 #ifdef __USE_SVID
115 /* Read an entry from STREAM.
116 This function is not part of POSIX and therefore no official
118 cancellation point. But due to similarity with an POSIX interface
119 or due to the implementation it is a cancellation point and
120 therefore not marked with __THROW. */
121 extern struct passwd *fgetpwent (FILE *__stream);
122 /* Write the given entry onto the given stream.
124 This function is not part of POSIX and therefore no official
126 cancellation point. But due to similarity with an POSIX interface
127 or due to the implementation it is a cancellation point and
128 therefore not marked with __THROW. */
129 extern int putpwent (const struct passwd *__restrict __p,
130 FILE *__restrict __f);
131 #endif
132 /* Search for an entry with a matching user ID.
134 This function is a possible cancellation point and therefore not
136 marked with __THROW. */
137 extern struct passwd *getpwuid (__uid_t __uid);
138 /* Search for an entry with a matching username.
140 This function is a possible cancellation point and therefore not
142 marked with __THROW. */
143 extern struct passwd *getpwnam (const char *__name);
144 #if defined __USE_POSIX || defined __USE_MISC
146 # ifdef __USE_MISC
148 /* Reasonable value for the buffer sized used in the reentrant
149 functions below. But better use `sysconf'. */
150 # define NSS_BUFLEN_PASSWD 1024
151 # endif
152 /* Reentrant versions of some of the functions above.
154 PLEASE NOTE: the `getpwent_r' function is not (yet) standardized.
156 The interface may change in later versions of this library. But
157 the interface is designed following the principals used for the
158 other reentrant functions so the chances are good this is what the
159 POSIX people would choose. */
160 # if defined __USE_SVID || defined __USE_MISC
162 /* This function is not part of POSIX and therefore no official
163 cancellation point. But due to similarity with an POSIX interface
164 or due to the implementation it is a cancellation point and
165 therefore not marked with __THROW. */
166 extern int getpwent_r (struct passwd *__restrict __resultbuf,
167 char *__restrict __buffer, size_t __buflen,
168 struct passwd **__restrict __result);
169 # endif
170 extern int getpwuid_r (__uid_t __uid,
172 struct passwd *__restrict __resultbuf,
173 char *__restrict __buffer, size_t __buflen,
174 struct passwd **__restrict __result);
175 extern int getpwnam_r (const char *__restrict __name,
177 struct passwd *__restrict __resultbuf,
178 char *__restrict __buffer, size_t __buflen,
179 struct passwd **__restrict __result);
180 # ifdef __USE_SVID
183 /* Read an entry from STREAM. This function is not standardized and
184 probably never will.
185 This function is not part of POSIX and therefore no official
187 cancellation point. But due to similarity with an POSIX interface
188 or due to the implementation it is a cancellation point and
189 therefore not marked with __THROW. */
190 extern int fgetpwent_r (FILE *__restrict __stream,
191 struct passwd *__restrict __resultbuf,
192 char *__restrict __buffer, size_t __buflen,
193 struct passwd **__restrict __result);
194 # endif
195 #endif /* POSIX or reentrant */
197 #ifdef __USE_GNU
199 /* Re-construct the password-file line for the given uid
200 in the given buffer. This knows the format that the caller
201 will expect, but this need not be the format of the password file.
202 This function is not part of POSIX and therefore no official
204 cancellation point. But due to similarity with an POSIX interface
205 or due to the implementation it is a cancellation point and
206 therefore not marked with __THROW. */
207 extern int getpw (__uid_t __uid, char *__buffer);
208 #endif
209 __END_DECLS
211 #endif /* pwd.h */
213 The fields pw_quota and pw_comment are unused; the others have meanings
215 described in passwd(5).
216 Getpwent reads the next line (opening the file if necessary); setpwent
218 rewinds the file; endpwent closes it.
219 Getpwuid and getpwnam search from the beginning until a matching uid or
221 name is found (or until EOF is encountered).
222
224 /etc/passwd
225
227 getlogin(3), getgrent(3), passwd(5)
228
230 Null pointer (0) returned on EOF or error.
231
233 All information is contained in a static area so it must be copied if
234 it is to be saved.
235 GETPWENT(3)