1ENDGRENT(3P) POSIX Programmer's Manual ENDGRENT(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 endgrent, getgrent, setgrent - group database entry functions
13
15 #include <grp.h>
16 void endgrent(void);
18 struct group *getgrent(void);
19 void setgrent(void);
20
23 The getgrent() function shall return a pointer to a structure contain‐
24 ing the broken-out fields of an entry in the group database. When first
25 called, getgrent() shall return a pointer to a group structure contain‐
26 ing the first entry in the group database. Thereafter, it shall return
27 a pointer to a group structure containing the next group structure in
28 the group database, so successive calls may be used to search the
29 entire database.
30 An implementation that provides extended security controls may impose
32 further implementation-defined restrictions on accessing the group
33 database. In particular, the system may deny the existence of some or
34 all of the group database entries associated with groups other than
35 those groups associated with the caller and may omit users other than
36 the caller from the list of members of groups in database entries that
37 are returned.
38 The setgrent() function shall rewind the group database to allow
40 repeated searches.
41 The endgrent() function may be called to close the group database when
43 processing is complete.
44 These functions need not be reentrant. A function that is not required
46 to be reentrant is not required to be thread-safe.
47
49 When first called, getgrent() shall return a pointer to the first group
50 structure in the group database. Upon subsequent calls it shall return
51 the next group structure in the group database. The getgrent() func‐
52 tion shall return a null pointer on end-of-file or an error and errno
53 may be set to indicate the error.
54 The return value may point to a static area which is overwritten by a
56 subsequent call to getgrgid(), getgrnam(), or getgrent().
57
59 The getgrent() function may fail if:
60 EINTR A signal was caught during the operation.
62 EIO An I/O error has occurred.
64 EMFILE {OPEN_MAX} file descriptors are currently open in the calling
66 process.
67 ENFILE The maximum allowable number of files is currently open in the
69 system.
70 The following sections are informative.
73
75 None.
76
78 These functions are provided due to their historical usage. Applica‐
79 tions should avoid dependencies on fields in the group database,
80 whether the database is a single file, or where in the file system name
81 space the database resides. Applications should use getgrnam() and get‐
82 grgid() whenever possible because it avoids these dependencies.
83
85 None.
86
88 None.
89
91 getgrgid(), getgrnam(), getlogin(), getpwent(), the Base Definitions
92 volume of IEEE Std 1003.1-2001, <grp.h>
93
95 Portions of this text are reprinted and reproduced in electronic form
96 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
97 -- Portable Operating System Interface (POSIX), The Open Group Base
98 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
99 Electrical and Electronics Engineers, Inc and The Open Group. In the
100 event of any discrepancy between this version and the original IEEE and
101 The Open Group Standard, the original IEEE and The Open Group Standard
102 is the referee document. The original Standard can be obtained online
103 at http://www.opengroup.org/unix/online.html .
104IEEE/The Open Group 2003 ENDGRENT(3P)