GETGRNAM(3P)                                        POSIX Programmer's Manual                                       GETGRNAM(3P)



PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (con-
       sult the corresponding Linux manual page for details of Linux behavior), or the  interface  may  not  be  implemented  on
       Linux.

NAME
       getgrnam, getgrnam_r - search group database for a name

SYNOPSIS
       #include <grp.h>

       struct group *getgrnam(const char *name);


       int getgrnam_r(const char *name, struct group *grp, char *buffer,
              size_t bufsize, struct group **result);


DESCRIPTION
       The getgrnam() function shall search the group database for an entry with a matching name.

       The  getgrnam()  function  need  not  be reentrant. A function that is not required to be reentrant is not required to be
       thread-safe.

       The getgrnam_r() function shall update the group structure pointed to by grp and store a pointer to that structure at the
       location  pointed to by result. The structure shall contain an entry from the group database with a matching gid or name.
       Storage referenced by the group structure is allocated from the memory provided with the buffer parameter, which is  buf-
       size  bytes  in size. The maximum size needed for this buffer can be determined with the {_SC_GETGR_R_SIZE_MAX} sysconf()
       parameter. A NULL pointer is returned at the location pointed to by result on error or if  the  requested  entry  is  not
       found.

RETURN VALUE
       The  getgrnam()  function  shall return a pointer to a struct group with the structure defined in <grp.h> with a matching
       entry if one is found. The getgrnam() function shall return a null pointer if either the requested entry was  not  found,
       or an error occurred. On error, errno shall be set to indicate the error.

       The  return value may point to a static area which is overwritten by a subsequent call to getgrent(), getgrgid(), or get-
       grnam().

       If successful, the getgrnam_r() function shall return zero; otherwise, an error number shall be returned to indicate  the
       error.

ERRORS
       The getgrnam() and getgrnam_r() functions may fail if:

       EIO    An I/O error has occurred.

       EINTR  A signal was caught during getgrnam().

       EMFILE {OPEN_MAX} file descriptors are currently open in the calling process.

       ENFILE The maximum allowable number of files is currently open in the system.


       The getgrnam_r() function may fail if:

       ERANGE Insufficient  storage  was  supplied  via buffer and bufsize to contain the data to be referenced by the resulting
              group structure.


       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       Applications wishing to check for error situations should set errno to 0 before calling getgrnam(). If errno  is  set  on
       return, an error occurred.

       The  getgrnam_r()  function  is thread-safe and shall return values in a user-supplied buffer instead of possibly using a
       static data area that may be overwritten by each call.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       endgrent(), getgrgid(), the Base Definitions volume of IEEE Std 1003.1-2001, <grp.h>, <limits.h>, <sys/types.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003  Edition,  Standard  for
       Information  Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copy-
       right (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any
       discrepancy  between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group
       Standard  is  the  referee   document.   The   original   Standard   can   be   obtained   online   at   http://www.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                  GETGRNAM(3P)