Name
getpwent_r, fgetpwent_r — get passwd file entry reentrantly
Synopsis
#include <pwd.h>
int
getpwent_r( |
struct passwd * | pwbuf, |
| char * | buf, | |
| size_t | buflen, | |
| struct passwd ** | pwbufp); |
int
fgetpwent_r( |
FILE * | fp, |
| struct passwd * | pwbuf, | |
| char * | buf, | |
| size_t | buflen, | |
| struct passwd ** | pwbufp); |
![[Note]](../stylesheet/note.png) |
Note | |||
|---|---|---|---|---|
|
DESCRIPTION
The functions getpwent_r()
and fgetpwent_r() are the
reentrant versions of getpwent(3) and fgetpwent(3). The former
reads the next passwd entry from the stream initialized by
setpwent(3). The latter
reads the next passwd entry from the stream fp given as parameter.
The passwd structure is
defined in <pwd.h> as
follows:
struct passwd { char * pw_name;char * pw_passwd;uid_t pw_uid;gid_t pw_gid;char * pw_gecos;char * pw_dir;char * pw_shell;};
The non-reentrant functions return a pointer to static
storage, where this static storage contains further pointers
to user name, password, gecos field, home directory and
shell. The reentrant functions described here return all of
that in caller-provided buffers. First of all there is the
buffer pwbuf that can
hold a struct passwd.
And next the buffer buf of size buflen that can hold additional
strings. The result of these functions, the struct passwd read from the
stream, is stored in the provided buffer *pwbuf, and a pointer to this
struct passwd is
returned in *pwbufp.
RETURN VALUE
On success, these functions return 0 and *pwbufp is a pointer to the
struct passwd. On
error, these functions return an error value and *pwbufp is NULL.
ERRORS
- ENOENT
-
No more entries.
- ERANGE
-
Insufficient buffer space supplied. Try again with larger buffer.
CONFORMING TO
These functions are GNU extensions, done in a style resembling the POSIX version of functions like getpwnam_r(3). Other systems use prototype
struct passwd * getpwent_r(struct passwd *pwd, char *buf, int buflen);
or, better,
int getpwent_r(struct passwd *pwd, char *buf, int buflen, FILE **pw_fp);
NOTES
The function getpwent_r() is
not really reentrant since it shares the reading position in
the stream with all other threads.
EXAMPLE
#define _GNU_SOURCE
#include <pwd.h>
#include <stdio.h>
#define BUFLEN 4096
int
main(void)
{
struct passwd pw, *pwp;
char buf[BUFLEN];
int i;
setpwent();
while (1) {
i = getpwent_r(&pw, buf, BUFLEN, &pwp);
if (i)
break;
printf("%s (%d)\tHOME %s\tSHELL %s\n", pwp−>pw_name,
pwp−>pw_uid, pwp−>pw_dir, pwp−>pw_shell);
}
endpwent();
exit(EXIT_SUCCESS);
}
COLOPHON
This page is part of release 2.79 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at
http://www.kernel.org/doc/man-pages/.
|
Copyright (c) 2003 Andries Brouwer (aebcwi.nl) This is free documentation; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. The GNU General Public License's references to "object code" and "executables" are to be interpreted as the output of any document formatting or typesetting system, including intermediate and printed output. This manual is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this manual; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA. |