Documentation for gnutls_ocsp_status_request_is_checked() is incorrect
The documentation for the function gnutls_ocsp_status_request_is_checked() states that the function takes a flags value that should either be 0 or GNUTLS_OCSP_SR_IS_AVAIL.
However, in version 3.3.21, GNUTLS_OCSP_SR_IS_AVAIL is not defined, and examination of the source code gnutls_ui.c shows that flags is in fact ignored.
Although the documentation available from the GnuTLS web site is for the latest version, notes on differences from previous versions should be more complete.
Furthermore, it is not clear from the documentation how to proceed with OSCP checking if the function returns 0. A return value of 0 means that either OSCP status response wasn't included in the handshake, or that the response was invalid. Does the user program have to carry out OSCP checks explicitly in this case?