Replace "iff" with "if and only if"

iff means if and only if, but readers without that knowledge might
assume this to be a spelling mistake. To me, this seems like
exclusionary language that is unnecessary. Simply using "if and only if"
instead should suffice.

1 files changed, 1 insertions, 1 deletions

diff --git a/st.c b/st.c
index dd7870562e..5b178f6b69 100644
--- a/st.c
+++ b/st.c
@@ -768,7 +768,7 @@ rebuild_table(st_table *tab)
    guarantees traversing all table bins in extreme case.
 
    According the Hull-Dobell theorem a generator
-   "Xnext = (a*Xprev + c) mod m" is a full cycle generator iff
+   "Xnext = (a*Xprev + c) mod m" is a full cycle generator if and only if
      o m and c are relatively prime
      o a-1 is divisible by all prime factors of m
      o a-1 is divisible by 4 if m is divisible by 4.