GETGRNAM(3)

NAME
getgrnam, getgrgid - get group file entry

SYNOPSIS
#include <grp.h>
#include <sys/types.h>

struct group *getgrnam(const char *name);

struct group *getgrgid(gid_t gid);

DESCRIPTION
The getgrnam() function returns a pointer to a structure containing the group information from /etc/group for the entry that matches the group name name.

The getgrgid() function returns a pointer to a structure containing the group information from /etc/group for the entry that matches the group gid gid.

The group structure is defined in <grp.h> as follows:

    struct group {
            char    *gr_name;        /* group name */
            char    *gr_passwd;      /* group password */
            gid_t   gr_gid;          /* group id */
            char    **gr_mem;        /* group members */
    };

RETURN VALUE
The getgrnam() and getgrgid() functions return a pointer to the group information structure, or NULL if the matching entry is not found or an error occurs. If an error occurs, errno is set appropriately.

The return value may point to static area, and may be overwritten by subsequent calls.

ERRORS

0 or ENOENT or ESRCH or EBADF or EPERM or ...
    The given name or gid was not found.

ENOMEM
    Insufficient memory.

EIO I/O error.

EINTR
    A signal was caught.

EMFILE
    The maximum number (OPEN_MAX) of files was open already in the calling process.

ENFILE
    The maximum number of files was open already in the system.

FILES

/etc/group
    Group database file

CONFORMING TO
SVID 3, POSIX, BSD 4.3

NOTES
The formulation given above under "RETURN VALUE" is from POSIX 1003.1-2001. It does not call "not found" an error, hence does not specify what value errno might have in this situation. But that makes it impossible to recognize errors. One might argue that according to POSIX errno should be left unchanged if an entry is not found. Experiments on various Unix-like systems shows that lots of different values occur in this situation: 0, ENOENT, EBADF, ESRCH, EWOULDBLOCK, EPERM and probably others.

SEE ALSO
fgetgrent(3), getgrent(3), setgrent(3), endgrent(3)