This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       None.

       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 .

IEEE/The Open Group                                   2017                                       SETEUID(3POSIX)

       If  uid  is  equal  to  the  real  user  ID  or  the saved set-user-ID, or if the process has appropriate
       privileges, seteuid() shall set the effective user ID of the calling process to uid; the real user ID and
       saved set-user-ID shall remain unchanged.

       The seteuid() function shall not affect the supplementary group list in any way.

       The seteuid() function shall fail if:

       EINVAL The value of the uid argument is invalid and is not supported by the implementation.

       EPERM  The  process  does  not have appropriate privileges and uid does not match the real user ID or the
              saved set-user-ID.

       Thefollowingsectionsareinformative.

       None.

       None.

       seteuid — set effective user ID

       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.

       Refer to the RATIONALE section in setuid().

       Upon successful completion, 0 shall be returned; otherwise,  -1  shall  be  returned  and  errno  set  to
       indicate the error.

exec, getegid(), geteuid(), getgid(), getuid(), setegid(), setgid(), setregid(), setreuid(), setuid()

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

       #include <unistd.h>

       int seteuid(uid_t uid);