@deftypefun {int} {gnutls_compress_certificate_set_methods} (gnutls_session_t @var{session}, const gnutls_compression_method_t * @var{methods}, size_t @var{methods_len}) @var{session}: is a @code{gnutls_session_t} type. @var{methods}: is a list of supported compression methods. @var{methods_len}: number of compression methods in @code{methods} This function sets the supported compression methods for certificate compression for the given session. The list of supported compression methods will be used for a) requesting the compression of peer's certificate and b) selecting the method to compress the local certificate before sending it to the peer. The order of compression methods inside the list does matter as the method that appears earlier in the list will be preffered before the later ones. Note that even if you set the list of supported compression methods, the compression might not be used if the peer does not support any of your chosen compression methods. The list of supported compression methods must meet the following criteria: Argument @code{methods} must be an array of valid compression methods of type @code{gnutls_compression_method_t} . Argument @code{methods_len} must contain the number of compression methods stored in the @code{methods} array and must be within range <1, 127>. The length constraints are defined by @code{MIN_COMPRESS_CERTIFICATE_METHODS} and @code{MAX_COMPRESS_CERTIFICATE_METHODS} macros located in the header file compress_certificate.h. If either @code{methods} or @code{methods_len} is equal to 0, current list of supported compression methods will be unset. @strong{Returns:} @code{GNUTLS_E_SUCCESS} on success, otherwise a negative error code. Since 3.7.4 @end deftypefun