hpux man page for setreuid

setreuid(2)							System Calls Manual						       setreuid(2)

NAME
       setreuid - set real and effective user IDs

SYNOPSIS
DESCRIPTION
       The function sets the real and effective user IDs of the current process to the values specified by the ruid and euid arguments. If ruid or
       euid is -1, the corresponding effective or real user ID of the current process is left unchanged.

       A process with appropriate privileges can set either ID to any value. An unprivileged process can only set the effective  user  ID  if  the
       euid argument is equal to either the real, effective, or saved user ID of the process.

       It  is  unspecified  whether  a	process  without appropriate privileges is permitted to change the real user ID to match the current real,
       effective or saved user ID of the process.

RETURN VALUE
       Upon successful completion, 0 is returned. Otherwise, -1 is returned and is set to indicate the error.

ERRORS
       The function will fail if:

	      [EINVAL]		       The value of the ruid or euid argument is invalid or out-of-range.

	      [EPERM]		       The current process does not have appropriate privileges, and either an attempt	was  made  to  change  the
				       effective user ID to a value other than the real user ID or the saved set-user-ID or an attempt was made to
				       change the real user ID to a value not permitted by the implementation.

SEE ALSO
       getuid(2), setuid(2), <unistd.h>.

CHANGE HISTORY
       First released in Issue 4, Version 2.

																       setreuid(2)