get_value   Use this callback function to get the specified parameter's value. The following example gets the value for parameter 1.

result = extapi->get_value( arg_handle, 1, &arg ) if( result == 0 || arg.data == NULL ) { return; // no parameter or parameter is NULL }

get_piece   Use this callback function to get the next chunk of the specified parameter's value (if there are any). The following example gets the remaining pieces for parameter 1.

cmd = (char *)malloc( arg.len.total_len + 1 ); offset = 0; for( ; result != 0; ) { if( arg.data == NULL ) break; memcpy( &cmd[offset], arg.data, arg.piece_len ); offset += arg.piece_len; cmd[offset] = '\0'; if( arg.piece_len == 0 ) break; result = extapi->get_piece( arg_handle, 1, &arg, offset ); }

set_value   Use this callback function to set the specified parameter's value. The following example sets the return value (parameter 0) for a RETURNS clause of a FUNCTION.

an_extfn_value retval; int ret = -1; // set up the return value struct retval.type = DT_INT; retval.data = (void*) &ret; retval.piece_len = retval.len.total_len = (a_sql_uint32) sizeof( int ); extapi->set_value( arg_handle, 0, &retval, 0 );

set_cancel   Use this callback function to establish a pointer to a variable that can be set by the extfn_cancel method. The following is example.

short canceled = 0; extapi->set_cancel( arg_handle, &canceled );