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Linux 2.6 - man page for getgrnam_r (linux section 3posix)

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

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 reen-
       trant 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 con-
       tain 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 bufsize 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 getgrnam().

       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, Copyright (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 orig-
       inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group			       2003				      GETGRNAM(P)


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