trusty (3) getgrnam_r.3posix.gz

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 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
       original Standard can be obtained online at http://www.opengroup.org/unix/online.html .