diff --git a/src/_cffi_src/openssl/x509v3.py b/src/_cffi_src/openssl/x509v3.py
index 550665c..cdd6df9 100644
--- a/src/_cffi_src/openssl/x509v3.py
+++ b/src/_cffi_src/openssl/x509v3.py
@@ -206,7 +206,7 @@
 void OTHERNAME_free(OTHERNAME *);
 
 POLICY_CONSTRAINTS *POLICY_CONSTRAINTS_new(void);
-POLICY_CONSTRAINTS_free(POLICY_CONSTRAINTS *);
+void POLICY_CONSTRAINTS_free(POLICY_CONSTRAINTS *);
 int i2d_POLICY_CONSTRAINTS(POLICY_CONSTRAINTS *, unsigned char **);
 
 void *X509V3_set_ctx_nodb(X509V3_CTX *);