diff --git a/cryptography/hazmat/bindings/openssl/dsa.py b/cryptography/hazmat/bindings/openssl/dsa.py
index 51a0266..a530589 100644
--- a/cryptography/hazmat/bindings/openssl/dsa.py
+++ b/cryptography/hazmat/bindings/openssl/dsa.py
@@ -47,6 +47,7 @@
 void DSA_SIG_free(DSA_SIG *);
 int i2d_DSA_SIG(const DSA_SIG *, unsigned char **);
 DSA_SIG *d2i_DSA_SIG(DSA_SIG **, const unsigned char **, long);
+int DSA_size(const DSA *);
 """
 
 MACROS = """