diff --git a/lib/isc/win32/libisc.def.in b/lib/isc/win32/libisc.def.in
index 332f247a61..4e112f2722 100644
--- a/lib/isc/win32/libisc.def.in
+++ b/lib/isc/win32/libisc.def.in
@@ -360,6 +360,7 @@ isc_lex_openbuffer
 isc_lex_openfile
 isc_lex_openstream
 isc_lex_setcomments
+isc_lex_setsourceline
 isc_lex_setsourcename
 isc_lex_setspecials
 isc_lex_ungettoken