getpwent, setpwent, endpwent - get password file entry
#include <sys/types.h>
#include <pwd.h>
struct passwd *getpwent(void);
void setpwent(void);
void endpwent(void);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
getpwent(),
setpwent(),
endpwent():
_XOPEN_SOURCE >= 500
|| /* Glibc since 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
The
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
/etc/passwd, NIS, and LDAP). The first time
getpwent() is called, it returns the first entry; thereafter, it
returns successive entries.
The
setpwent() function rewinds to the beginning of the password
database.
The
endpwent() function is used to close the password database after all
processing has been performed.
The
passwd structure is defined in
<pwd.h> as follows:
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 */
};
For more information about the fields of this structure, see
passwd(5).
The
getpwent() function returns a pointer to a
passwd structure,
or NULL if there are no more entries or an error occurred. If an error occurs,
errno is set appropriately. If one wants to check
errno after
the call, it should be set to zero before the call.
The return value may point to a static area, and may be overwritten by
subsequent calls to
getpwent(),
getpwnam(3), or
getpwuid(3). (Do not pass the returned pointer to
free(3).)
- EINTR
- A signal was caught; see signal(7).
- EIO
- I/O error.
- EMFILE
- The per-process limit on the number of open file descriptors has been
reached.
- ENFILE
- The system-wide limit on the total number of open files has been
reached.
- ENOMEM
- Insufficient memory to allocate passwd structure.
- ERANGE
- Insufficient buffer space supplied.
- /etc/passwd
- local password database file
For an explanation of the terms used in this section, see
attributes(7).
Interface |
Attribute |
Value |
getpwent () |
Thread safety |
MT-Unsafe race:pwent race:pwentbuf locale |
setpwent (), endpwent () |
Thread safety |
MT-Unsafe race:pwent locale |
In the above table,
pwent in
race:pwent signifies that if any of
the functions
setpwent(),
getpwent(), or
endpwent() are
used in parallel in different threads of a program, then data races could
occur.
POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD. The
pw_gecos field is not
specified in POSIX, but is present on most implementations.
fgetpwent(3),
getpw(3),
getpwent_r(3),
getpwnam(3),
getpwuid(3),
putpwent(3),
passwd(5)