1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
3 .\" Permission is granted to make and distribute verbatim copies of this
4 .\" manual provided the copyright notice and this permission notice are
5 .\" preserved on all copies.
7 .\" Permission is granted to copy and distribute modified versions of this
8 .\" manual under the conditions for verbatim copying, provided that the
9 .\" entire resulting derived work is distributed under the terms of a
10 .\" permission notice identical to this one.
12 .\" Since the Linux kernel and libraries are constantly changing, this
13 .\" manual page may be incorrect or out-of-date. The author(s) assume no
14 .\" responsibility for errors or omissions, or for damages resulting from
15 .\" the use of the information contained herein. The author(s) may not
16 .\" have taken the same level of care in the production of this manual,
17 .\" which is licensed free of charge, as they might when working
20 .\" Formatted or processed versions of this manual, if unaccompanied by
21 .\" the source, must acknowledge the copyright and authors of this work.
23 .\" References consulted:
24 .\" Linux libc source code
25 .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
28 .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
29 .\" Modified 2003-11-15 by aeb
31 .TH GETGRNAM 3 2012-04-23 "" "Linux Programmer's Manual"
33 getgrnam, getgrnam_r, getgrgid, getgrgid_r \- get group file entry
36 .B #include <sys/types.h>
39 .BI "struct group *getgrnam(const char *" name );
41 .BI "struct group *getgrgid(gid_t " gid );
43 .BI "int getgrnam_r(const char *" name ", struct group *" grp ,
45 .BI " char *" buf ", size_t " buflen ", struct group **" result );
47 .BI "int getgrgid_r(gid_t " gid ", struct group *" grp ,
49 .BI " char *" buf ", size_t " buflen ", struct group **" result );
53 Feature Test Macro Requirements for glibc (see
54 .BR feature_test_macros (7)):
61 _POSIX_C_SOURCE\ >=\ 1 || _XOPEN_SOURCE || _BSD_SOURCE ||
62 _SVID_SOURCE || _POSIX_SOURCE
68 function returns a pointer to a structure containing
69 the broken-out fields of the record in the group database
70 (e.g., the local group file
73 that matches the group name
78 function returns a pointer to a structure containing
79 the broken-out fields of the record in the group database
80 that matches the group ID
83 The \fIgroup\fP structure is defined in \fI<grp.h>\fP as follows:
88 char *gr_name; /* group name */
89 char *gr_passwd; /* group password */
90 gid_t gr_gid; /* group ID */
91 char **gr_mem; /* group members */
96 For more information about the fields of this structure, see
103 functions obtain the same information as
107 but store the retrieved
110 in the space pointed to by
112 The string fields pointed to by the members of the
114 structure are stored in the buffer
118 A pointer to the result (in case of success) or NULL (in case no entry
119 was found or an error occurred) is stored in
124 sysconf(_SC_GETGR_R_SIZE_MAX)
126 returns either \-1, without changing
128 or an initial suggested size for
130 (If this size is too small,
133 in which case the caller can retry with a larger buffer.)
139 functions return a pointer to a
141 structure, or NULL if the matching entry
142 is not found or an error occurs.
145 is set appropriately.
146 If one wants to check
148 after the call, it should be set to zero before the call.
150 The return value may point to a static area, and may be overwritten
151 by subsequent calls to
156 (Do not pass the returned pointer to
167 If no matching group record was found,
168 these functions return 0 and store NULL in
170 In case of error, an error number is returned, and NULL is stored in
174 .BR 0 " or " ENOENT " or " ESRCH " or " EBADF " or " EPERM " or ... "
190 of files was open already in the calling process.
193 The maximum number of files was open already in the system.
197 Insufficient memory to allocate
200 .\" to allocate the group structure, or to allocate buffers
203 Insufficient buffer space supplied.
207 local group database file
209 SVr4, 4.3BSD, POSIX.1-2001.
211 The formulation given above under "RETURN VALUE" is from POSIX.1-2001.
212 It does not call "not found" an error, hence does not specify what value
214 might have in this situation.
215 But that makes it impossible to recognize
217 One might argue that according to POSIX
219 should be left unchanged if an entry is not found.
220 Experiments on various
221 UNIX-like systems shows that lots of different values occur in this
222 situation: 0, ENOENT, EBADF, ESRCH, EWOULDBLOCK, EPERM and probably others.
224 .\" AIX 5.1 - gives ESRCH
225 .\" OSF1 4.0g - gives EWOULDBLOCK
226 .\" libc, glibc up to version 2.6, Irix 6.5 - give ENOENT
227 .\" glibc since version 2.7 - give 0
228 .\" FreeBSD 4.8, OpenBSD 3.2, NetBSD 1.6 - give EPERM
229 .\" SunOS 5.8 - gives EBADF
230 .\" Tru64 5.1b, HP-UX-11i, SunOS 5.7 - give 0