diff --git a/src/eval.c b/src/eval.c
index 990fa8c..9091f79 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -26439,6 +26439,8 @@
 
     if (src[*usedlen] == ':' && src[*usedlen + 1] == 'S')
     {
+	/* vim_strsave_shellescape() needs a NUL terminated string. */
+	(*fnamep)[*fnamelen] = NUL;
 	p = vim_strsave_shellescape(*fnamep, FALSE, FALSE);
 	if (p == NULL)
 	    return -1;
diff --git a/src/testdir/test105.in b/src/testdir/test105.in
index 58c4f84..9921d7e 100644
--- a/src/testdir/test105.in
+++ b/src/testdir/test105.in
@@ -35,6 +35,7 @@
 :Put fnamemodify('abc'' ''def',    ':S'      )
 :Put fnamemodify('abc''%''def',    ':S'      )
 :Put fnamemodify("abc\ndef",       ':S'      )
+:Put expand('%:r:S') == shellescape(expand('%:r'))
 :set shell=tcsh
 :Put fnamemodify("abc\ndef",       ':S'      )
 :$put ='vim: ts=8'
diff --git a/src/testdir/test105.ok b/src/testdir/test105.ok
index 5f1de5f..584f0fe 100644
--- a/src/testdir/test105.ok
+++ b/src/testdir/test105.ok
@@ -25,5 +25,6 @@
 fnamemodify('abc'' ''def',    ':S'      )	'''abc''\'''' ''\''''def'''
 fnamemodify('abc''%''def',    ':S'      )	'''abc''\''''%''\''''def'''
 fnamemodify("abc\ndef",       ':S'      )	'''abc^@def'''
+expand('%:r:S') == shellescape(expand('%:r'))	1
 fnamemodify("abc\ndef",       ':S'      )	'''abc\^@def'''
 vim: ts=8
diff --git a/src/version.c b/src/version.c
index c9c550a..465794a 100644
--- a/src/version.c
+++ b/src/version.c
@@ -749,6 +749,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1641,
+/**/
     1640,
 /**/
     1639,