man3/fgetgrent.3

   1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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  25 .\" References consulted:
  26 .\"     Linux libc source code
  27 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
  28 .\"     386BSD man pages
  29 .\" Modified Sat Jul 24 19:38:44 1993 by Rik Faith (faith@cs.unc.edu)
  30 .TH FGETGRENT 3  2015-12-05 "GNU" "Linux Programmer's Manual"
  31 .SH NAME
  32 fgetgrent \- get group file entry
  33 .SH SYNOPSIS
  34 .nf
  35 .B #include <stdio.h>
  36 .B #include <sys/types.h>
  37 .B #include <grp.h>
  38 .sp
  39 .BI "struct group *fgetgrent(FILE *" stream );
  40 .fi
  41 .sp
  42 .in -4n
  43 Feature Test Macro Requirements for glibc (see
  44 .BR feature_test_macros (7)):
  45 .in
  46 .sp
  47 .BR fgetgrent ():
  48     Since glibc 2.19:
  49         _DEFAULT_SOURCE
  50     Glibc 2.19 and earlier:
  51         _SVID_SOURCE
  52 .SH DESCRIPTION
  53 The
  54 .BR fgetgrent ()
  55 function returns a pointer to a structure containing
  56 the group information from the file referred to by
  57 .IR stream .
  58 The first time it is called
  59 it returns the first entry; thereafter, it returns successive entries.
  60 The file referred to by
  61 .I stream
  62 must have the same format as
  63 .I /etc/group
  64 (see
  65 .BR group (5)).
  66 .PP
  67 The \fIgroup\fP structure is defined in \fI<grp.h>\fP as follows:
  68 .sp
  69 .in +4n
  70 .nf
  71 struct group {
  72     char   *gr_name;        /* group name */
  73     char   *gr_passwd;      /* group password */
  74     gid_t   gr_gid;         /* group ID */
  75     char  **gr_mem;         /* NULL-terminated array of pointers
  76                                to names of group members */
  77 };
  78 .fi
  79 .in
  80 .SH RETURN VALUE
  81 The
  82 .BR fgetgrent ()
  83 function returns a pointer to a
  84 .I group
  85 structure,
  86 or NULL if there are no more entries or an error occurs.
  87 In the event of an error,
  88 .I errno
  89 is set to indicate the cause.
  90 .SH ERRORS
  91 .TP
  92 .B ENOMEM
  93 Insufficient memory to allocate
  94 .I group
  95 structure.
  96 .SH ATTRIBUTES
  97 For an explanation of the terms used in this section, see
  98 .BR attributes (7).
  99 .TS
 100 allbox;
 101 lb lb lb
 102 l l l.
 103 Interface       Attribute       Value
 104 T{
 105 .BR fgetgrent ()
 106 .\" FIXME: the following marking is different from which in glibc manual,
 107 .\" marking in glibc manual is,
 108 .\" fgetgrent: MT-Unsafe race:fgrent
 109 .\" We think race:fgrent in glibc maybe hard for users to understand,
 110 .\" and have sent a patch to the GNU libc community for changing it to
 111 .\" race:fgetgrent, however, something about the copyright impeded the progress.
 112 T}      Thread safety   MT-Unsafe race:fgetgrent
 113 .TE
 114
 115 .SH CONFORMING TO
 116 SVr4.
 117 .SH SEE ALSO
 118 .BR endgrent (3),
 119 .BR fgetgrent_r (3),
 120 .BR fopen (3),
 121 .BR getgrent (3),
 122 .BR getgrgid (3),
 123 .BR getgrnam (3),
 124 .BR putgrent (3),
 125 .BR setgrent (3),
 126 .BR group (5)