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

library “libssl” libcrypto
#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.