sendfile.2: Add notes on sendfile64()

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

diff --git a/man2/sendfile.2 b/man2/sendfile.2
index 12d4d3c7c488c4c384b37052ef81b652ce936c49..df6211403fc2504bc165f9c492d7aea2c138fccd 100644 (file)
--- a/man2/sendfile.2
+++ b/man2/sendfile.2
@@ -168,6 +168,18 @@ In Linux 2.4 and earlier,
 could refer to a regular file, and
 .BR sendfile ()
 changed the current offset of that file.
+
+The original Linux
+.BR sendfile ()
+system call was not designed to handle large file offsets.
+Consequently, Linux 2.4 added
+.BR sendfile64 (),
+with a wider type for the
+.I offset
+argument.
+The glibc
+.BR sendfile ()
+wrapper function transparently deals with the kernel differences.
 .SH "SEE ALSO"
 .BR mmap (2),
 .BR open (2),