|System Calls Manual
setreuid — set
real and effective user ID's
Standard C Library (libc, -lc)
The real and effective user IDs of the current process are set according to the arguments. If ruid or euid is -1, the current uid is filled in by the system. Unprivileged users may change the real user ID to the effective user ID and vice-versa; only the super-user may make other changes.
If the real user ID is changed (i.e. ruid is not -1) or the effective user ID is changed to something other than the real user ID, then the saved user ID will be set to the effective user ID.
system call has been used to swap the real and effective user IDs in
set-user-ID programs to temporarily relinquish the set-user-ID value. This
purpose is now better served by the use of the seteuid(2)
When setting the real and effective user IDs to the
same value, the standard
system call is preferred.
setreuid() function returns the
value 0 if successful; otherwise the value -1 is returned and
the global variable errno is set to indicate the
- The current process is not the super-user and a change other than changing the effective user-id to the real user-id was specified.
setreuid() system call appeared in
|February 8, 2001