diff --git a/lib/operators.c b/lib/operators.c
index 8c3bcba5..32dbbee8 100644
--- a/lib/operators.c
+++ b/lib/operators.c
@@ -36,7 +36,7 @@ for (idx=0; idx<nbiter; idx++) {
 	d->B[idx] = a->B[idx] + b->B[idx];
 	}
 
-return -1;
+return 0;
 }
 /* ---------------------------------------------------------------- */
 /*
@@ -63,7 +63,7 @@ for (idx=0; idx<nbiter; idx++) {
 	d->B[idx] = fabs(a->B[idx] - b->B[idx]);
 	}
 
-return -1;
+return 0;
 }
 /* ---------------------------------------------------------------- */
 /* ---------------------------------------------------------------- */
@@ -91,6 +91,6 @@ for (idx=0; idx<nbiter; idx++) {
 	d->B[idx] = a->B[idx] * b->B[idx];
 	}
 
-return -1;
+return 0;
 }
 /* ---------------------------------------------------------------- */