retitle 990265 mksh: output error is not checked for some builtins reopen 990265 thanks
On 2021-06-24 13:49:55 +0000, Thorsten Glaser wrote: > At the start of those commands, stdout is closed, so you violate that > constraint. Note POSIX is not just demands on the implementation but > also on the user, for example, it specifically permits extensions where > the behaviour is otherwise unspecified, i.e. which could not happen in > a conforming user. [...] Note that here, pwd is a builtin, so that there is no "program start-up". So no constraints are violated. Anyway, this was just an example. So, instead of a closed stdout, let's write to a full file system: $ pwd > /dev/full $ echo $? 0 $ /bin/pwd > /dev/full /bin/pwd: write error: No space left on device $ echo $? 1 With the mksh builtin, the error is not detected. Whatever POSIX says, it is important to report an error in such a case, at least for the robustness of scripts. Same problem with ksh93. -- Vincent Lefèvre <vinc...@vinc17.net> - Web: <https://www.vinc17.net/> 100% accessible validated (X)HTML - Blog: <https://www.vinc17.net/blog/> Work: CR INRIA - computer arithmetic / AriC project (LIP, ENS-Lyon)
