diff --git a/ext/openssl/ossl_pkcs7.c b/ext/openssl/ossl_pkcs7.c
index 79bc5d76f..3cf5820c3 100644
--- a/ext/openssl/ossl_pkcs7.c
+++ b/ext/openssl/ossl_pkcs7.c
@@ -979,7 +979,7 @@ ossl_pkcs7si_initialize(VALUE self, VALUE cert, VALUE key, VALUE digest)
     x509 = GetX509CertPtr(cert); /* NO NEED TO DUP */
     md = ossl_evp_md_fetch(digest, &md_holder);
     GetPKCS7si(self, p7si);
-    if (!(PKCS7_SIGNER_INFO_set(p7si, x509, pkey, md)))
+    if (PKCS7_SIGNER_INFO_set(p7si, x509, pkey, md) <= 0)
         ossl_raise(ePKCS7Error, "PKCS7_SIGNER_INFO_set");
     rb_ivar_set(self, id_md_holder, md_holder);