Clarify return values for EVP_DigestVerifyFinal.

Previous language was unclear.  New language isn't pretty but I believe
it is more accurate.

Signed-off-by: Rich Salz <rsalz@openssl.org>
Reviewed-by: Ben Laurie <ben@openssl.org>
Reviewed-by: Richard Levitte <levitte@openssl.org>
(cherry picked from commit 8cbb048c3ea416f2bd8a3706d027f3aa26ef08d9)

diff --git a/doc/crypto/EVP_DigestVerifyInit.pod b/doc/crypto/EVP_DigestVerifyInit.pod
index cfeccd96effcfbe54c8237f0b6e1d2781c172532..54cad92e6fd172b8ce216e0db43dc87d92d9ee27 100644 (file)
--- a/doc/crypto/EVP_DigestVerifyInit.pod
+++ b/doc/crypto/EVP_DigestVerifyInit.pod
@@ -37,10 +37,11 @@ EVP_DigestVerifyInit() and EVP_DigestVerifyUpdate() return 1 for success and 0
 or a negative value for failure. In particular a return value of -2 indicates
 the operation is not supported by the public key algorithm.
 
-Unlike other functions the return value 0 from EVP_DigestVerifyFinal() only
-indicates that the signature did not verify successfully (that is tbs did
-not match the original data or the signature was of invalid form) it is not an
-indication of a more serious error.
+EVP_DigestVerifyFinal() returns 1 for success; any other value indicates
+failure.  A return value of zero indicates that the signature did not verify
+successfully (that is, tbs did not match the original data or the signature had
+an invalid form), while other values indicate a more serious error (and
+sometimes also indicate an invalid signature form).
 
 The error codes can be obtained from L<ERR_get_error(3)|ERR_get_error(3)>.