mirror of
https://github.com/openssl/openssl.git
synced 2024-12-17 05:53:49 +08:00
77 lines
2.3 KiB
Plaintext
77 lines
2.3 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
SSL_read - write bytes to a TLS/SSL connection.
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/ssl.h>
|
|
|
|
int SSL_write(SSL *ssl, char *buf, int num);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
SSL_write() writes B<num> bytes from the buffer B<buf> into the specified
|
|
B<ssl> connection.
|
|
|
|
=head1 NOTES
|
|
|
|
If necessary, SSL_write() will negotiate a TLS/SSL session, if
|
|
not already explicitly performed by SSL_connect() or SSL_accept(). If the
|
|
peer requests a re-negotiation, it will be performed transparently during
|
|
the SSL_write() operation. The behaviour of SSL_write() depends on the
|
|
underlying BIO.
|
|
|
|
If the underlying BIO is B<blocking>, SSL_write() will only return, once the
|
|
write operation has been finished or an error occurred.
|
|
|
|
If the underlying BIO is B<non-blocking>, SSL_write() will also return,
|
|
when the underlying BIO could not satisfy the needs of SSL_write()
|
|
to continue the operation. In this case a call to SSL_get_error() with the
|
|
return value of SSL_write() will yield B<SSL_ERROR_WANT_READ> or
|
|
B<SSL_ERROR_WANT_WRITE>. As at any time a re-negotiation is possible, a
|
|
call to SSL_write() can also cause write operations! The calling process
|
|
then must repeat the call after taking appropriate action to satisfy the
|
|
needs of SSL_write(). The action depends on the underlying BIO. When using a
|
|
non-blocking socket, nothing is to be done, but select() can be used to check
|
|
for the required condition. When using a buffering BIO, like a BIO pair, data
|
|
must be written into or retrieved out of the BIO before being able to continue.
|
|
|
|
=head1 IMPORTANT
|
|
|
|
When an SSL_write() operation has to be repeated because of
|
|
B<SSL_ERROR_WANT_READ> or B<SSL_ERROR_WANT_WRITE>, it must be repeated
|
|
with the same arguments.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
The following return values can occur:
|
|
|
|
=over 4
|
|
|
|
=item E<gt>0
|
|
|
|
The write operation was successful, the return value is the number of
|
|
bytes actually written to the TLS/SSL connection.
|
|
|
|
=item 0
|
|
|
|
The write operation was not successful. Call SSL_get_error() with the return
|
|
value B<ret> to find out, whether an error occurred.
|
|
|
|
=item -1
|
|
|
|
The read operation was not successful, because either an error occurred
|
|
or action must be taken by the calling process. Call SSL_get_error() with the
|
|
return value B<ret> to find out the reason.
|
|
|
|
=back
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<SSL_get_error(3)|SSL_get_error(3)>, L<SSL_read(3)|SSL_read(3)>,
|
|
L<ssl(3)|ssl(3)>, L<bio(3)|bio(3)>
|
|
|
|
=cut
|