setregid - Sets the real and effective group ID
gid_t egid );
Interfaces documented on this reference page conform to industry standards
Refer to the standards(5) reference page for more information about indus-
try standards and associated tags.
rgid Specifies the new real group ID.
egid Specifies the new effective group ID.
The setregid() function sets the real group ID of the current process to
the value specified by the rgid parameter, and sets the effective group ID
to the value specified by the egid parameter. If the value of rgid is -1,
the real group ID is not changed; if the value of egid is -1, the effective
group ID is not changed. The real and effective group IDs may be set to
different values in the same call.
Unprivileged users may change the effective group ID to the real group ID;
only the superuser may make other changes.
Any supplementary group IDs of the calling process remain unchanged.
Upon successful completion, a value of 0 (zero) is returned. Otherwise, a
value of -1 is returned and errno is set to indicate the error.
The setregid() function sets errno to the specified values for the follow-
[EINVAL] The value of the rgid egid parameter is invalid or out of range.
[EPERM] The current process does not have superuser privilege and a
change other than changing the effective group ID to the real
group ID was specified.
Functions: getgid(2), setgid(2), setrgid(3), setreuid(2)