diff options
Diffstat (limited to 'crypto/openssl/doc/ssl/SSL_read.pod')
-rw-r--r-- | crypto/openssl/doc/ssl/SSL_read.pod | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/crypto/openssl/doc/ssl/SSL_read.pod b/crypto/openssl/doc/ssl/SSL_read.pod new file mode 100644 index 0000000..072dc26 --- /dev/null +++ b/crypto/openssl/doc/ssl/SSL_read.pod @@ -0,0 +1,77 @@ +=pod + +=head1 NAME + +SSL_read - read bytes from a TLS/SSL connection. + +=head1 SYNOPSIS + + #include <openssl/ssl.h> + + int SSL_read(SSL *ssl, char *buf, int num); + +=head1 DESCRIPTION + +SSL_read() tries to read B<num> bytes from the specified B<ssl> into the +buffer B<buf>. + +=head1 NOTES + +If necessary, SSL_read() 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_read() operation. The behaviour of SSL_read() depends on the +underlying BIO. + +If the underlying BIO is B<blocking>, SSL_read() will only return, once the +read operation has been finished or an error occurred. + +If the underlying BIO is B<non-blocking>, SSL_read() will also return +when the underlying BIO could not satisfy the needs of SSL_read() +to continue the operation. In this case a call to SSL_get_error() with the +return value of SSL_read() 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_read() can also cause write operations! The calling process +then must repeat the call after taking appropriate action to satisfy the +needs of SSL_read(). 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 WARNING + +When an SSL_read() 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 read operation was successful; the return value is the number of +bytes actually read from the TLS/SSL connection. + +=item 0 + +The read operation was not successful, probably because no data was +available. 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_write(3)|SSL_write(3)>, +L<ssl(3)|ssl(3)>, L<bio(3)|bio(3)> + +=cut |