Provided by: manpages-dev_3.21-1_all bug

NAME

       getgrnam, getgrnam_r, getgrgid, getgrgid_r - get group file entry

SYNOPSIS

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

       struct group *getgrnam(const char *name);

       struct group *getgrgid(gid_t gid);

       int getgrnam_r(const char *name, struct group *grp,
                 char *buf, size_t buflen, struct group **result);

       int getgrgid_r(gid_t gid, struct group *grp,
                 char *buf, size_t buflen, struct group **result);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       getgrnam_r(), getgrgid_r(): _POSIX_C_SOURCE >= 1 || _XOPEN_SOURCE ||
       _BSD_SOURCE || _SVID_SOURCE || _POSIX_SOURCE

DESCRIPTION

       The getgrnam() function returns a pointer to a structure containing the
       broken-out  fields of the record in the group database (e.g., the local
       group file /etc/group, NIS, and LDAP) that matches the group name name.

       The getgrgid() function returns a pointer to a structure containing the
       broken-out fields of the record in the group database that matches  the
       group ID gid.

       The   getgrnam_r()   and   getgrgid_r()   functions   obtain  the  same
       information, but store the  retrieved  group  structure  in  the  space
       pointed  to by grp.  This group structure contains pointers to strings,
       and these strings are stored in the  buffer  buf  of  size  buflen.   A
       pointer  to  the  result (in case of success) or NULL (in case no entry
       was found or an error occurred) is stored in *result.

       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 */
           };

       The maximum needed size for buf can be found using sysconf(3) with  the
       argument _SC_GETGR_R_SIZE_MAX.

RETURN VALUE

       The  getgrnam()  and  getgrgid()  functions return a pointer to a group
       structure, or NULL if the matching entry  is  not  found  or  an  error
       occurs.   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 getgrent(3), getgrgid(), or  getgrnam().   (Do  not
       pass the returned pointer to free(3).)

       On  success, getgrnam_r() and getgrgid_r() return zero, and set *result
       to grp.  If no matching group record was found, these functions  return
       0  and  store  NULL  in  *result.  In case of error, an error number is
       returned, and NULL is stored in *result.

ERRORS

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

       EINTR  A signal was caught.

       EIO    I/O error.

       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.

       ENOMEM Insufficient memory to allocate group structure.

       ERANGE Insufficient buffer space supplied.

FILES

       /etc/group
              local group database file

CONFORMING TO

       SVr4, 4.3BSD, POSIX.1-2001.

NOTES

       The  formulation given above under "RETURN VALUE" is from POSIX.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

       endgrent(3),  fgetgrent(3),  getgrent(3),   getpwnam(3),   setgrent(3),
       group(5)

COLOPHON

       This  page  is  part of release 3.21 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/.

                                  2009-03-30                       GETGRNAM(3)