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



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

SYNOPSIS
       #include <&lt;sys/types.h>&gt;
       #include <&lt;grp.h>&gt;

       struct group *getgrnam(const char *name);

       struct group *getgrgid(gid_t gid);

       int getgrnam_r(const char *name, struct group *gbuf,
                 char *buf, size_t buflen, struct group **gbufp);

       int getgrgid_r(gid_t gid, struct group *gbuf,
                 char *buf, size_t buflen, struct group **gbufp);

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 informa-
       tion, but store the retrieved group structure in the space  pointed  to
       by  gbuf.  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 *gbufp.

       The group structure is defined in &lt;grp.h&gt; 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 static area, and may be overwritten by
       subsequent calls to getgrent(3), getgrgid(), or getgrnam().

       The getgrnam_r() and getgrgid_r() functions return zero on success.  In
       case of error, an error number is returned.

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 var-
       ious  Unix-like  systems  shows  that lots of different values occur in
       this situation: 0, ENOENT, EBADF, ESRCH, EWOULDBLOCK, EPERM and  proba-
       bly others.

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

COLOPHON
       This page is part of release 3.05 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/.



                                  2003-11-15                       GETGRNAM(3)