SSL_want, SSL_want_nothing, SSL_want_read, SSL_want_write, SSL_want_x509_lookup — obtain state information TLS/SSL I/O operation
int SSL_want_nothing(SSL *ssl);
int SSL_want_write(SSL *ssl);
SSL_want() returns state information for the SSL object ssl.
The other SSL_want_*() calls are shortcuts for the possible
states returned by SSL_want().
SSL_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).
The following return values can currently occur for SSL_want():
There is no data to be written or to be read.
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.
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
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.
ssl(3), err(3), SSL_get_error(3)