setreuid(2)                       SDK R4.11                      setreuid(2)


NAME
       setreuid - set the real-, effective-, and saved-user-ids

SYNOPSIS
       #include <sys/types.h>

       int  setreuid (ruid, euid)
       uidt  ruid;
       uidt  euid;

   where:
       ruid      The value to which the real-user-id should be set

       euid      The value to which the effective-user-id should be set

DESCRIPTION
       The real-user-id and effective-user-id's of the calling process are
       set according to the arguments.  If ruid or euid is -1, the current
       value of the real-user-id is used.  If the calling process does not
       have appropriate privilege, he may only set the effective-user-id to
       the real-user-id or the saved_user_id.  For systems supporting the
       DG/UX Capability Option, appropriate privilege is defined as having
       one or more specific capabilities enabled in the effective capability
       set of the calling process.  See capdefaults(5) for the default
       capability for this system call.

       On systems without the DG/UX Capability Option, appropriate privilege
       means that the process has an effective UID of root. (See the
       appropriateprivilege(5) man page for more information.)  Only a
       calling process with appropriate privilege may make other changes.
       If after changing the real- and effective-user-id's, the calling
       process's effective-user-id no longer matches either its real- or
       saved-user-id's, its saved-user-id is set to the value of its
       effective-user-id.

ACCESS CONTROL
       If the calling process has appropriate privilege, setting of the
       real- and effective-user-ids is not restricted.

       Otherwise, the effective-user-id may be set only to its current value
       or to the current value of the real-user-id or to the saved-user-id
       value.  The real-user-id may be set only to its current value.

RETURN VALUE
       0      Successful completion.

       -1     An error occurred.  errno is set to indicate the error.

DIAGNOSTICS
       Errno may be set to one of the following error codes:

       EPERM     The above specified access check failed.

       EINVAL    The supplied value of ruid or euid was less than -1 or
                 greater than MAXUID.

SEE ALSO
       getuid(2), geteuid(2), getgid(2), getegid(2), setuid(2), setgid(2),
       appropriateprivilege(5).
       capdefaults(5).


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