setreuid(2)setreuid(2)NAMEsetreuid - set real and effective user IDs
SYNOPSISDESCRIPTION
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 cur‐
rent 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, effec‐
tive 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 effec‐
tive 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 ALSOgetuid(2), setuid(2), <unistd.h>.
CHANGE HISTORY
First released in Issue 4, Version 2.
setreuid(2)