Cryptography and SSL/TLS Toolkit



SSL_CTX_set_read_ahead, SSL_CTX_get_read_ahead, SSL_set_read_ahead, SSL_get_read_ahead, SSL_CTX_get_default_read_ahead - manage whether to read as many input bytes as possible


 #include <openssl/ssl.h>

 void SSL_set_read_ahead(SSL *s, int yes);
 int SSL_get_read_ahead(const SSL *s);

 SSL_CTX_set_read_ahead(SSL_CTX *ctx, int yes);
 long SSL_CTX_get_read_ahead(SSL_CTX *ctx);
 long SSL_CTX_get_default_read_ahead(SSL_CTX *ctx);


SSL_CTX_set_read_ahead() and SSL_set_read_ahead() set whether we should read as many input bytes as possible (for non-blocking reads) or not. For example if x bytes are currently required by OpenSSL, but y bytes are available from the underlying BIO (where y > x), then OpenSSL will read all y bytes into its buffer (providing that the buffer is large enough) if reading ahead is on, or x bytes otherwise. The parameter yes or m should be 0 to ensure reading ahead is off, or non zero otherwise. SSL_CTX_set_default_read_ahead() is identical to SSL_CTX_set_read_ahead().

SSL_CTX_get_read_ahead() and SSL_get_read_ahead() indicate whether reading ahead has been set or not.


These functions have no impact when used with DTLS. The return values for SSL_CTX_get_read_head() and SSL_get_read_ahead() are undefined for DTLS. Setting read_ahead can impact the behaviour of the SSL_pending() function (see SSL_pending(3)).


SSL_get_read_ahead() and SSL_CTX_get_read_ahead() return 0 if reading ahead is off, and non zero otherwise.


ssl(3), SSL_pending(3)

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Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at