title: What does PKCS5_PBKDF2_HMAC_SHA1 return value mean?
body: <p>I'm attempting to use OpenSSL's <a href="http://cvs.openssl.org/fileview?f=openssl/crypto/evp/p5_crpt2.c&amp;v=1.25.4.3" rel="nofollow">PKCS5_PBKDF2_HMAC_SHA1</a> method. I gather that it returns 0 if it succeeds, and some other value otherwise. My question is, what does a non-zero return value mean? Memory error? Usage error? How should my program handle it (retry, quit?)?</p>
  
  <p>Edit: A corollary question is, is there any way to figure this out besides reverse-engineering the method itself?</p>