1 files changed, 14 insertions, 0 deletions
diff --git a/doc/mailfromd.texi b/doc/mailfromd.texi
index b583341d..731c4ae1 100644
--- a/doc/mailfromd.texi
+++ b/doc/mailfromd.texi
@@ -4984,6 +4984,20 @@ message body obtained from the remote host.
 As of version @value{VERSION}, @code{$1} cannot be processed with
 usual string functions, because it is not null-terminated.  This
 limitation will be removed in future versions.
+
+It is possible, however, to pass it to an external program, using
+@code{write} with three arguments (@pxref{I/O functions, write}), e.g.:
+
+@smallexample
+number fd;
+
+prog body
+do
+  write(fd, $1, $2);
+  @dots{}
+@end smallexample
+
+  This example assumes that @code{fd} is opened using @code{open}.  
 @end table
 @end deffn