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
13 endgrent, getgrent, setgrent — group database entry functions
14
16 #include <grp.h>
17 void endgrent(void);
19 struct group *getgrent(void);
20 void setgrent(void);
21
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 thread-safe.
46
48 When first called, getgrent() shall return a pointer to the first group
49 structure in the group database. Upon subsequent calls it shall return
50 the next group structure in the group database. The getgrent() function
51 shall return a null pointer on end-of-file or an error and errno may be
52 set to indicate the error.
53 The application shall not modify the structure to which the return
55 value points, nor any storage areas pointed to by pointers within the
56 structure. The returned pointer, and pointers within the structure,
57 might be invalidated or the structure or the storage areas might be
58 overwritten by a subsequent call to getgrgid(), getgrnam(), or get‐
59 grent().
60
62 The getgrent() function may fail if:
63 EINTR A signal was caught during the operation.
65 EIO An I/O error has occurred.
67 EMFILE All file descriptors available to the process are currently
69 open.
70 ENFILE The maximum allowable number of files is currently open in the
72 system.
73 The following sections are informative.
75
77 None.
78
80 These functions are provided due to their historical usage. Applica‐
81 tions should avoid dependencies on fields in the group database,
82 whether the database is a single file, or where in the file system name
83 space the database resides. Applications should use getgrnam() and get‐
84 grgid() whenever possible because it avoids these dependencies.
85
87 None.
88
90 None.
91
93 endpwent(), getgrgid(), getgrnam(), getlogin()
94 The Base Definitions volume of POSIX.1‐2008, <grp.h>
96
98 Portions of this text are reprinted and reproduced in electronic form
99 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
100 -- Portable Operating System Interface (POSIX), The Open Group Base
101 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
102 cal and Electronics Engineers, Inc and The Open Group. (This is
103 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
104 event of any discrepancy between this version and the original IEEE and
105 The Open Group Standard, the original IEEE and The Open Group Standard
106 is the referee document. The original Standard can be obtained online
107 at http://www.unix.org/online.html .
108 Any typographical or formatting errors that appear in this page are
110 most likely to have been introduced during the conversion of the source
111 files to man page format. To report such errors, see https://www.ker‐
112 nel.org/doc/man-pages/reporting_bugs.html .
113IEEE/The Open Group 2013 ENDGRENT(3P)