diff --git a/tests/symbol-scan.pl b/tests/symbol-scan.pl
index 2f9ce3507ac5bd72d05aa086232a6b292545e190..f12660339b614fa93266c30cfe29e6c0d53ae109 100644
--- a/tests/symbol-scan.pl
+++ b/tests/symbol-scan.pl
@@ -35,7 +35,7 @@ my $verbose=0;
 my $summary=0;
 my $misses=0;
 
-open H_IN, "-|", "cpp", $h;
+open H_IN, "-|", "cpp " . $h;
 while ( <H_IN> ) {
     if ( /enum\s+(\S+\s+)?{/ .. /}/ ) {
         s/^\s+//;