Meaning of SYSCALL fields

I'm documenting the fields of certain auditd messages for RHEL 4. Amongst the SYSCALL fields are the following uid/gid related fields. uid (obvious) gid (obvious) euid (obvious) suid - what's this? fsuid - what's this? egid (obvious) sgid - what's this? fsgid - what's this? Can anybody fill in the blanks for me? Thanks, Matt -- Matthew Booth, RHCA, RHCSS Red Hat, Global Professional Services M: +44 (0)7977 267231 GPG ID: D33C3490 GPG FPR: 3733 612D 2D05 5458 8A8A 1600 3441 EA19 D33C 3490