[openssl-users] SSL_read preserving message boundaries.

Dr. Stephen Henson steve at openssl.org
Sat Mar 7 17:03:56 UTC 2015

On Sat, Mar 07, 2015, dE wrote:

> Suppose, I write a small amount of data with SSL_write. Will openssl
> accumulate these writes to make a single big fragment and then send
> it, or will it send it the moment it receives the data, as a single
> fragment?

No it tries to send the data with each call. That's because you might (for
example) be using a character mode application which should send each keypress
as soon as possible.

If you use BIOs you can make use of a buffering BIO which will accumulate
writes until either the buffer is full or you explicitly flush it.

Dr Stephen N. Henson. OpenSSL project core developer.
Commercial tech support now available see: http://www.openssl.org

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