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Diffstat (limited to 'doc/man3/BIO_f_buffer.pod')
| -rw-r--r-- | doc/man3/BIO_f_buffer.pod | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/doc/man3/BIO_f_buffer.pod b/doc/man3/BIO_f_buffer.pod index 8ceaaa3c0343..047a11d2407c 100644 --- a/doc/man3/BIO_f_buffer.pod +++ b/doc/man3/BIO_f_buffer.pod @@ -49,10 +49,20 @@ is expanded. These functions, other than BIO_f_buffer(), are implemented as macros. -Buffering BIOs implement BIO_gets() by using BIO_read_ex() operations on the -next BIO in the chain. By prepending a buffering BIO to a chain it is therefore -possible to provide BIO_gets() functionality if the following BIOs do not -support it (for example SSL BIOs). +Buffering BIOs implement BIO_read_ex() and BIO_gets() by using +BIO_read_ex() operations on the next BIO in the chain and storing the +result in an internal buffer, from which bytes are given back to the +caller as appropriate for the call; a BIO_gets() is guaranteed to give +the caller a whole line, and BIO_read_ex() is guaranteed to give the +caller the number of bytes it asks for, unless there's an error or end +of communication is reached in the next BIO. By prepending a +buffering BIO to a chain it is therefore possible to provide +BIO_gets() or exact size BIO_read_ex() functionality if the following +BIOs do not support it. + +Do not add more than one BIO_f_buffer() to a BIO chain. The result of +doing so will force a full read of the size of the internal buffer of +the top BIO_f_buffer(), which is 4 KiB at a minimum. Data is only written to the next BIO in the chain when the write buffer fills or when BIO_flush() is called. It is therefore important to call BIO_flush() @@ -82,7 +92,7 @@ L<BIO_ctrl(3)>. =head1 COPYRIGHT -Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. +Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved. Licensed under the OpenSSL license (the "License"). You may not use this file except in compliance with the License. You can obtain a copy |