FGETPWENT(3) Linux Programmer's Manual FGETPWENT(3)

fgetpwent - get password file entry

#include <stdio.h>
#include <sys/types.h>
#include <pwd.h>
struct passwd *fgetpwent(FILE *stream);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
fgetpwent():
Since glibc 2.19:
_DEFAULT_SOURCE
Glibc 2.19 and earlier:
_SVID_SOURCE

The fgetpwent() function returns a pointer to a structure containing the broken out fields of a line in the file stream. The first time it is called it returns the first entry; thereafter, it returns successive entries. The file referred to by stream must have the same format as /etc/passwd (see passwd(5)).
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;      /* real name */
    char   *pw_dir;        /* home directory */
    char   *pw_shell;      /* shell program */
};

The fgetpwent() function returns a pointer to a passwd structure, or NULL if there are no more entries or an error occurs. In the event of an error, errno is set to indicate the cause.

ENOMEM
Insufficient memory to allocate passwd structure.

/etc/passwd
password database file

For an explanation of the terms used in this section, see attributes(7).
Interface Attribute Value
fgetpwent () Thread safety MT-Unsafe race:fgetpwent

SVr4.

endpwent(3), fgetpwent_r(3), fopen(3), getpw(3), getpwent(3), getpwnam(3), getpwuid(3), putpwent(3), setpwent(3), passwd(5)
2018-02-02 GNU