SSL_want, SSL_want_nothing, SSL_want_read, SSL_want_write, SSL_want_x509_lookup - obtain state information TLS/SSL I/O operation
Synopsis #include <openssl/ssl.h> int
SSL_want(SSL *ssl); int SSL_want_nothing(SSL *ssl); int
SSL_want_read(SSL *ssl); int SSL_want_write(SSL *ssl); int
SSL_want_x509_lookup(SSL *ssl);
DESCRIPTIONSSL_want() returns state information for the SSL object ssl.
The other SSL_want_*() calls are shortcuts for the possible
states returned by SSL_want().
NOTESSSL_want() examines the internal state information of the
SSL object. Its return values are similar to that of SSL_get_error(3) .
Unlike SSL_get_error(3) , which also evaluates the
error queue, the results are obtained by examining an internal state
flag only. The information must therefore only be used for normal
operation under non-blocking I/O. Error conditions are not handled
and must be treated using SSL_get_error(3) .
The result returned by SSL_want() should always be consistent
with the result of SSL_get_error(3) .
RETURN VALUESThe following return values can currently occur for SSL_want():
SSL_NOTHING There is no data to be written or to be read.
SSL_WRITING There are data in the SSL buffer that must be written to the
underlying BIO layer in order to complete the actual SSL_*() operation.
A call to SSL_get_error(3) should return SSL_ERROR_WANT_WRITE.
SSL_READING More data must be read from the underlying BIO layer in order
to complete the actual SSL_*() operation. A call to SSL_get_error(3) should
return SSL_ERROR_WANT_READ.
SSL_X509_LOOKUP The operation did not complete because an application callback
set by SSL_CTX_set_client_cert_cb() has asked to be called again.
A call to SSL_get_error(3) should return SSL_ERROR_WANT_X509_LOOKUP.
SSL_want_nothing(), SSL_want_read(), SSL_want_write(), SSL_want_x509_lookup()
return 1, when the corresponding condition is true or 0 otherwise.
HP Open Source Security for OpenVMS Volume 2:... 
SSL Application Programming Interface (API) Reference
