SSL_write.pod revision 68651
1=pod 2 3=head1 NAME 4 5SSL_read - write bytes to a TLS/SSL connection. 6 7=head1 SYNOPSIS 8 9 #include <openssl/ssl.h> 10 11 int SSL_write(SSL *ssl, char *buf, int num); 12 13=head1 DESCRIPTION 14 15SSL_write() writes B<num> bytes from the buffer B<buf> into the specified 16B<ssl> connection. 17 18=head1 NOTES 19 20If necessary, SSL_write() will negotiate a TLS/SSL session, if 21not already explicitly performed by SSL_connect() or SSL_accept(). If the 22peer requests a re-negotiation, it will be performed transparently during 23the SSL_write() operation. The behaviour of SSL_write() depends on the 24underlying BIO. 25 26If the underlying BIO is B<blocking>, SSL_write() will only return, once the 27write operation has been finished or an error occurred. 28 29If the underlying BIO is B<non-blocking>, SSL_write() will also return, 30when the underlying BIO could not satisfy the needs of SSL_write() 31to continue the operation. In this case a call to SSL_get_error() with the 32return value of SSL_write() will yield B<SSL_ERROR_WANT_READ> or 33B<SSL_ERROR_WANT_WRITE>. As at any time a re-negotiation is possible, a 34call to SSL_write() can also cause write operations! The calling process 35then must repeat the call after taking appropriate action to satisfy the 36needs of SSL_write(). The action depends on the underlying BIO. When using a 37non-blocking socket, nothing is to be done, but select() can be used to check 38for the required condition. When using a buffering BIO, like a BIO pair, data 39must be written into or retrieved out of the BIO before being able to continue. 40 41=head1 WARNING 42 43When an SSL_write() operation has to be repeated because of 44B<SSL_ERROR_WANT_READ> or B<SSL_ERROR_WANT_WRITE>, it must be repeated 45with the same arguments. 46 47=head1 RETURN VALUES 48 49The following return values can occur: 50 51=over 4 52 53=item E<gt>0 54 55The write operation was successful, the return value is the number of 56bytes actually written to the TLS/SSL connection. 57 58=item 0 59 60The write operation was not successful. Call SSL_get_error() with the return 61value B<ret> to find out, whether an error occurred. 62 63=item -1 64 65The read operation was not successful, because either an error occurred 66or action must be taken by the calling process. Call SSL_get_error() with the 67return value B<ret> to find out the reason. 68 69=back 70 71=head1 SEE ALSO 72 73L<SSL_get_error(3)|SSL_get_error(3)>, L<SSL_read(3)|SSL_read(3)>, 74L<ssl(3)|ssl(3)>, L<bio(3)|bio(3)> 75 76=cut 77