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+'\" t
+.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
+.\"
+.\" SPDX-License-Identifier: Linux-man-pages-copyleft
+.\"
+.\" References consulted:
+.\" Linux libc source code
+.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
+.\" 386BSD man pages
+.\"
+.\" Modified Sat Jul 24 19:22:14 1993 by Rik Faith (faith@cs.unc.edu)
+.\" Modified Mon May 27 21:37:47 1996 by Martin Schulze (joey@linux.de)
+.\"
+.TH getpwent 3 2023-07-20 "Linux man-pages 6.05.01"
+.SH NAME
+getpwent, setpwent, endpwent \- get password file entry
+.SH LIBRARY
+Standard C library
+.RI ( libc ", " \-lc )
+.SH SYNOPSIS
+.nf
+.B #include <sys/types.h>
+.B #include <pwd.h>
+.PP
+.B struct passwd *getpwent(void);
+.B void setpwent(void);
+.B void endpwent(void);
+.fi
+.PP
+.RS -4
+Feature Test Macro Requirements for glibc (see
+.BR feature_test_macros (7)):
+.RE
+.PP
+.BR getpwent (),
+.BR setpwent (),
+.BR endpwent ():
+.nf
+ _XOPEN_SOURCE >= 500
+.\" || _XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED
+ || /* glibc >= 2.19: */ _DEFAULT_SOURCE
+ || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
+.fi
+.SH DESCRIPTION
+The
+.BR getpwent ()
+function returns a pointer to a structure containing
+the broken-out fields of a record from the password database
+(e.g., the local password file
+.IR /etc/passwd ,
+NIS, and LDAP).
+The first time
+.BR getpwent ()
+is called, it returns the first entry; thereafter, it returns successive
+entries.
+.PP
+The
+.BR setpwent ()
+function rewinds to the beginning
+of the password database.
+.PP
+The
+.BR endpwent ()
+function is used to close the password database
+after all processing has been performed.
+.PP
+The \fIpasswd\fP structure is defined in \fI<pwd.h>\fP as follows:
+.PP
+.in +4n
+.EX
+struct passwd {
+ char *pw_name; /* username */
+ char *pw_passwd; /* user password */
+ uid_t pw_uid; /* user ID */
+ gid_t pw_gid; /* group ID */
+ char *pw_gecos; /* user information */
+ char *pw_dir; /* home directory */
+ char *pw_shell; /* shell program */
+};
+.EE
+.in
+.PP
+For more information about the fields of this structure, see
+.BR passwd (5).
+.SH RETURN VALUE
+The
+.BR getpwent ()
+function returns a pointer to a
+.I passwd
+structure, or NULL if
+there are no more entries or an error occurred.
+If an error occurs,
+.I errno
+is set to indicate the error.
+If one wants to check
+.I errno
+after the call, it should be set to zero before the call.
+.PP
+The return value may point to a static area, and may be overwritten
+by subsequent calls to
+.BR getpwent (),
+.BR getpwnam (3),
+or
+.BR getpwuid (3).
+(Do not pass the returned pointer to
+.BR free (3).)
+.SH ERRORS
+.TP
+.B EINTR
+A signal was caught; see
+.BR signal (7).
+.TP
+.B EIO
+I/O error.
+.TP
+.B EMFILE
+The per-process limit on the number of open file descriptors has been reached.
+.TP
+.B ENFILE
+The system-wide limit on the total number of open files has been reached.
+.TP
+.B ENOMEM
+.\" not in POSIX
+Insufficient memory to allocate
+.I passwd
+structure.
+.\" to allocate the passwd structure, or to allocate buffers
+.TP
+.B ERANGE
+Insufficient buffer space supplied.
+.SH FILES
+.TP
+.I /etc/passwd
+local password database file
+.SH ATTRIBUTES
+For an explanation of the terms used in this section, see
+.BR attributes (7).
+.TS
+allbox;
+lb lb lbx
+l l l.
+Interface Attribute Value
+T{
+.na
+.nh
+.BR getpwent ()
+T} Thread safety T{
+.na
+.nh
+MT-Unsafe race:pwent
+race:pwentbuf locale
+T}
+T{
+.na
+.nh
+.BR setpwent (),
+.BR endpwent ()
+T} Thread safety T{
+.na
+.nh
+MT-Unsafe race:pwent locale
+T}
+.TE
+.sp 1
+In the above table,
+.I pwent
+in
+.I race:pwent
+signifies that if any of the functions
+.BR setpwent (),
+.BR getpwent (),
+or
+.BR endpwent ()
+are used in parallel in different threads of a program,
+then data races could occur.
+.SH VERSIONS
+The
+.I pw_gecos
+field is not specified in POSIX, but is present on most implementations.
+.SH STANDARDS
+POSIX.1-2008.
+.SH HISTORY
+POSIX.1-2001, SVr4, 4.3BSD.
+.SH SEE ALSO
+.BR fgetpwent (3),
+.BR getpw (3),
+.BR getpwent_r (3),
+.BR getpwnam (3),
+.BR getpwuid (3),
+.BR putpwent (3),
+.BR passwd (5)