The file size (as reported by
.BR stat (2))
will be changed if
-.I "offset + len"
+.IR offset + len
is greater than the file size.
This default behavior closely resembles the behavior of the
.BR posix_fallocate (3)
.IR mode ,
the behavior of the call is similar,
but the file size will not be changed even if
-.I "offset + len"
+.IR offset + len
is greater than the file size.
Preallocating zeroed blocks beyond the end of the file in this manner
is useful for optimizing append workloads.