man3/getpwent.3

   1 .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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  23 .\" References consulted:
  24 .\"     Linux libc source code
  25 .\"     Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
  26 .\"     386BSD man pages
  27 .\"
  28 .\" Modified Sat Jul 24 19:22:14 1993 by Rik Faith (faith@cs.unc.edu)
  29 .\" Modified Mon May 27 21:37:47 1996 by Martin Schulze (joey@linux.de)
  30 .\"
  31 .TH GETPWENT 3  1996-05-27 "GNU" "Linux Programmer's Manual"
  32 .SH NAME
  33 getpwent, setpwent, endpwent \- get password file entry
  34 .SH SYNOPSIS
  35 .nf
  36 .B #include <sys/types.h>
  37 .B #include <pwd.h>
  38 .sp
  39 .B struct passwd *getpwent(void);
  40 .sp
  41 .B void setpwent(void);
  42 .sp
  43 .B void endpwent(void);
  44 .fi
  45 .SH DESCRIPTION
  46 The \fBgetpwent\fP() function returns a pointer to a structure containing
  47 the broken-out fields of a record from the password database
  48 (e.g., the local password file
  49 .IR /etc/passwd ,
  50 NIS, and LDAP).
  51 The first time it
  52 is called it returns the first entry; thereafter, it returns successive
  53 entries.
  54 .PP
  55 The \fBsetpwent\fP() function rewinds to the beginning
  56 of the password database.
  57 .PP
  58 The \fBendpwent\fP() function is used to close the password database
  59 after all processing has been performed.
  60 .PP
  61 The \fIpasswd\fP structure is defined in \fI<pwd.h>\fP as follows:
  62 .sp
  63 .RS 0.25i
  64 .nf
  65 struct passwd {
  66     char   *pw_name;       /* user name */
  67     char   *pw_passwd;     /* user password */
  68     uid_t   pw_uid;        /* user ID */
  69     gid_t   pw_gid;        /* group ID */
  70     char   *pw_gecos;      /* real name */
  71     char   *pw_dir;        /* home directory */
  72     char   *pw_shell;      /* shell program */
  73 };
  74 .fi
  75 .RE
  76 .SH "RETURN VALUE"
  77 The \fBgetpwent\fP() function returns a pointer to a
  78 .I passwd
  79 structure, or NULL if
  80 there are no more entries or an error occurs.
  81 If an error occurs,
  82 .I errno
  83 is set appropriately.
  84 If one wants to check
  85 .I errno
  86 after the call, it should be set to zero before the call.
  87 .SH ERRORS
  88 .TP
  89 .B EINTR
  90 A signal was caught.
  91 .TP
  92 .B EIO
  93 I/O error.
  94 .TP
  95 .B EMFILE
  96 The maximum number (OPEN_MAX) of files was open already in the calling process.
  97 .TP
  98 .B ENFILE
  99 The maximum number of files was open already in the system.
 100 .TP
 101 .B ENOMEM
 102 .\" not in POSIX
 103 Insufficient memory to allocate passwd structure.
 104 .\" to allocate the passwd structure, or to allocate buffers
 105 .TP
 106 .B ERANGE
 107 Insufficient buffer space supplied.
 108 .SH FILES
 109 .TP
 110 .I /etc/passwd
 111 local password database file
 112 .SH "CONFORMING TO"
 113 SVr4, 4.3BSD, POSIX.1-2001.
 114 .SH "SEE ALSO"
 115 .BR fgetpwent (3),
 116 .BR getpw (3),
 117 .BR getpwent_r (3),
 118 .BR getpwnam (3),
 119 .BR getpwuid (3),
 120 .BR putpwent (3),
 121 .BR passwd (5)