1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
3 .\" %%%LICENSE_START(VERBATIM)
4 .\" Permission is granted to make and distribute verbatim copies of this
5 .\" manual provided the copyright notice and this permission notice are
6 .\" preserved on all copies.
8 .\" Permission is granted to copy and distribute modified versions of this
9 .\" manual under the conditions for verbatim copying, provided that the
10 .\" entire resulting derived work is distributed under the terms of a
11 .\" permission notice identical to this one.
13 .\" Since the Linux kernel and libraries are constantly changing, this
14 .\" manual page may be incorrect or out-of-date. The author(s) assume no
15 .\" responsibility for errors or omissions, or for damages resulting from
16 .\" the use of the information contained herein. The author(s) may not
17 .\" have taken the same level of care in the production of this manual,
18 .\" which is licensed free of charge, as they might when working
21 .\" Formatted or processed versions of this manual, if unaccompanied by
22 .\" the source, must acknowledge the copyright and authors of this work.
25 .\" References consulted:
26 .\" Linux libc source code
27 .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
30 .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
31 .\" Modified 2003-11-15 by aeb
33 .TH GETGRNAM 3 2013-07-22 "" "Linux Programmer's Manual"
35 getgrnam, getgrnam_r, getgrgid, getgrgid_r \- get group file entry
38 .B #include <sys/types.h>
41 .BI "struct group *getgrnam(const char *" name );
43 .BI "struct group *getgrgid(gid_t " gid );
45 .BI "int getgrnam_r(const char *" name ", struct group *" grp ,
47 .BI " char *" buf ", size_t " buflen ", struct group **" result );
49 .BI "int getgrgid_r(gid_t " gid ", struct group *" grp ,
51 .BI " char *" buf ", size_t " buflen ", struct group **" result );
55 Feature Test Macro Requirements for glibc (see
56 .BR feature_test_macros (7)):
63 _POSIX_C_SOURCE\ >=\ 1 || _XOPEN_SOURCE || _BSD_SOURCE ||
64 _SVID_SOURCE || _POSIX_SOURCE
70 function returns a pointer to a structure containing
71 the broken-out fields of the record in the group database
72 (e.g., the local group file
75 that matches the group name
80 function returns a pointer to a structure containing
81 the broken-out fields of the record in the group database
82 that matches the group ID
85 The \fIgroup\fP structure is defined in \fI<grp.h>\fP as follows:
90 char *gr_name; /* group name */
91 char *gr_passwd; /* group password */
92 gid_t gr_gid; /* group ID */
93 char **gr_mem; /* group members */
98 For more information about the fields of this structure, see
105 functions obtain the same information as
109 but store the retrieved
112 in the space pointed to by
114 The string fields pointed to by the members of the
116 structure are stored in the buffer
120 A pointer to the result (in case of success) or NULL (in case no entry
121 was found or an error occurred) is stored in
126 sysconf(_SC_GETGR_R_SIZE_MAX)
128 returns either \-1, without changing
130 or an initial suggested size for
132 (If this size is too small,
135 in which case the caller can retry with a larger buffer.)
141 functions return a pointer to a
143 structure, or NULL if the matching entry
144 is not found or an error occurs.
147 is set appropriately.
148 If one wants to check
150 after the call, it should be set to zero before the call.
152 The return value may point to a static area, and may be overwritten
153 by subsequent calls to
158 (Do not pass the returned pointer to
169 If no matching group record was found,
170 these functions return 0 and store NULL in
172 In case of error, an error number is returned, and NULL is stored in
176 .BR 0 " or " ENOENT " or " ESRCH " or " EBADF " or " EPERM " or ... "
192 of files was open already in the calling process.
195 The maximum number of files was open already in the system.
199 Insufficient memory to allocate
202 .\" to allocate the group structure, or to allocate buffers
205 Insufficient buffer space supplied.
209 local group database file
211 .SS Multithreading (see pthreads(7))
216 functions are not thread-safe.
222 functions are thread-safe.
224 SVr4, 4.3BSD, POSIX.1-2001.
226 The formulation given above under "RETURN VALUE" is from POSIX.1-2001.
227 It does not call "not found" an error, hence does not specify what value
229 might have in this situation.
230 But that makes it impossible to recognize
232 One might argue that according to POSIX
234 should be left unchanged if an entry is not found.
235 Experiments on various
236 UNIX-like systems shows that lots of different values occur in this
237 situation: 0, ENOENT, EBADF, ESRCH, EWOULDBLOCK, EPERM, and probably others.
239 .\" AIX 5.1 - gives ESRCH
240 .\" OSF1 4.0g - gives EWOULDBLOCK
241 .\" libc, glibc up to version 2.6, Irix 6.5 - give ENOENT
242 .\" glibc since version 2.7 - give 0
243 .\" FreeBSD 4.8, OpenBSD 3.2, NetBSD 1.6 - give EPERM
244 .\" SunOS 5.8 - gives EBADF
245 .\" Tru64 5.1b, HP-UX-11i, SunOS 5.7 - give 0
254 This page is part of release 3.67 of the Linux
257 A description of the project,
258 information about reporting bugs,
259 and the latest version of this page,
261 \%http://www.kernel.org/doc/man\-pages/.