Clarify getfsstat(2) usage.

The getfsstat(2) function expects a buffer and a count, and returns a count.

The confusing part is that the count it takes is a byte count, while the
return value is a count of the number of structures it has filled out.

Spell this out.

1 files changed, 6 insertions, 1 deletions

diff --git a/lib/libc/sys/getfsstat.2 b/lib/libc/sys/getfsstat.2
index 41d9904..3100d93 100644
--- a/lib/libc/sys/getfsstat.2
+++ b/lib/libc/sys/getfsstat.2
@@ -63,8 +63,13 @@ Fields that are undefined for a particular file system are set to -1.
 The buffer is filled with an array of
 .Fa fsstat
 structures, one for each mounted file system
-up to the size specified by
+up to the byte count specified by
 .Fa bufsize .
+Note, the
+.Fa bufsize
+argument is the number of bytes that
+.Fa buf
+can hold, not the count of statfs structures it will hold.
 .Pp
 If
 .Fa buf