SSL_WANT(3) Library Functions Manual SSL_WANT(3)
NAME
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(const SSL *ssl);
int
SSL_want_nothing(const SSL *ssl);
int
SSL_want_read(const SSL *ssl);
int
SSL_want_write(const SSL *ssl);
int
SSL_want_x509_lookup(const SSL *ssl);
DESCRIPTION
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 those 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 VALUES
The 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(3) 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(), and SSL_want_x509_lookup() return 1 when the corresponding condition is true or 0 otherwise.
SEE ALSO
err(3), ssl(3), SSL_get_error(3)
HISTORY
SSL_want(), SSL_want_nothing(), SSL_want_read(), and SSL_want_write() first appeared in SSLeay 0.5.2. SSL_want_x509_lookup() first appeared in SSLeay 0.6.0. These functions have been available since OpenBSD 2.4. GNU March 27, 2018 SSL_WANT(3)