diff --git a/eo/test/t-eo.cpp b/eo/test/t-eo.cpp
index 86b0f723..38236253 100644
--- a/eo/test/t-eo.cpp
+++ b/eo/test/t-eo.cpp
@@ -10,12 +10,14 @@ typedef EO<float> Chrom;
 
 //-----------------------------------------------------------------------------
 
-main()
+int main()
 {
   Chrom chrom1, chrom2;
 
   cout << "chrom1 = " << chrom1 << endl
        << "chrom2 = " << chrom2 << endl;
+
+  return 1;
 }
 
 //-----------------------------------------------------------------------------