PROLOG

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

NAME

       geteuid — get the effective user ID

SYNOPSIS

       #include <unistd.h>

       uid_t geteuid(void);

DESCRIPTION

       The  geteuid()  function  shall  return the effective user ID of the calling process.  The
       geteuid() function shall not modify errno.

RETURN VALUE

       The geteuid() function shall always be successful and  no  return  value  is  reserved  to
       indicate an error.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       In   a  conforming  environment,  geteuid()  will  always  succeed.  It  is  possible  for
       implementations to provide an extension where a process in  a  non-conforming  environment
       will   not  be  associated  with  a  user  or  group  ID.  It  is  recommended  that  such
       implementations return (uid_t)-1 and set errno to indicate such an environment;  doing  so
       does not violate this standard, since such an environment is already an extension.

FUTURE DIRECTIONS

       None.

SEE ALSO

       getegid(),  getgid(),  getuid(),  setegid(),  seteuid(), setgid(), setregid(), setreuid(),
       setuid()

       The Base Definitions volume of POSIX.1‐2017, <sys_types.h>, <unistd.h>

COPYRIGHT

       Portions of this text are reprinted and  reproduced  in  electronic  form  from  IEEE  Std
       1003.1-2017,  Standard  for  Information Technology -- Portable Operating System Interface
       (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C)  2018  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 .

       Any typographical or formatting errors that appear in this page are most  likely  to  have
       been  introduced  during  the conversion of the source files to man page format. To report
       such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html .