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'\" t
.\" Copyright, the authors of the Linux man-pages project
.\"
.\" SPDX-License-Identifier: Linux-man-pages-copyleft
.\"
.TH getpw 3 2025-05-17 "Linux man-pages (unreleased)"
.SH NAME
getpw \- reconstruct password line entry
.SH LIBRARY
Standard C library
.RI ( libc ,\~ \-lc )
.SH SYNOPSIS
.nf
.BR "#define _GNU_SOURCE" " /* See feature_test_macros(7) */"
.B #include <sys/types.h>
.B #include <pwd.h>
.P
.BI "[[deprecated]] int getpw(uid_t " uid ", char *" buf );
.fi
.SH DESCRIPTION
The
.BR getpw ()
function reconstructs the password line entry for
the given user ID
.I uid
in the buffer
.IR buf .
The returned buffer contains a line of format
.P
.in +4n
.EX
.B name:passwd:uid:gid:gecos:dir:shell
.EE
.in
.P
The
.I passwd
structure is defined in
.I <pwd.h>
as follows:
.P
.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
.P
For more information about the fields of this structure, see
.BR passwd (5).
.SH RETURN VALUE
The
.BR getpw ()
function returns 0 on success; on error, it returns \-1, and
.I errno
is set to indicate the error.
.P
If
.I uid
is not found in the password database,
.BR getpw ()
returns \-1, sets
.I errno
to 0, and leaves
.I buf
unchanged.
.SH ERRORS
.TP
.BR 0 " or " ENOENT
No user corresponding to
.IR uid .
.TP
.B EINVAL
.I buf
is NULL.
.TP
.B ENOMEM
Insufficient memory to allocate
.I passwd
structure.
.SH FILES
.TP
.I /etc/passwd
password database file
.SH ATTRIBUTES
For an explanation of the terms used in this section, see
.BR attributes (7).
.TS
allbox;
lbx lb lb
l l l.
Interface Attribute Value
T{
.na
.nh
.BR getpw ()
T} Thread safety MT-Safe locale
.TE
.SH STANDARDS
None.
.SH HISTORY
SVr2.
.SH BUGS
The
.BR getpw ()
function is dangerous as it may overflow the provided buffer
.IR buf .
It is obsoleted by
.BR getpwuid (3).
.SH SEE ALSO
.BR endpwent (3),
.BR fgetpwent (3),
.BR getpwent (3),
.BR getpwnam (3),
.BR getpwuid (3),
.BR putpwent (3),
.BR setpwent (3),
.BR passwd (5)
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