Hi, Sorry wanted to close, but forgot to use done.
So I opened a bug with upstream: https://bugs.launchpad.net/sbcl/+bug/2126919 and turns out this is undefined behaviour: >It is not legal. From >https://www.lispworks.com/documentation/HyperSpec/Body/m_w_in_f.htm > >"The input string stream to which the variable var is bound has dynamic >extent; its extent ends when the form is exited." > >Same for the values of variables bound by WITH-OUTPUT-TO-STRING, >WITH-OPEN-STREAM, WITH-OPEN-FILE. Closing as such. Best regards, Peter
