yy_switch_to_buffer
void yy_switch_to_buffer (YY_BUFFER_STATE new_buffer );
yy_switch_to_buffer(yy_create_buffer(input,YY_BUF_SIZE));
yy_switch_to_buffer(s->buffer);
yy_switch_to_buffer(b );
void yy_switch_to_buffer( struct yy_buffer_state* new_buffer );
yy_switch_to_buffer( struct yy_buffer_state* new_buffer ) = 0;