Hacker News new | ask | show | jobs
by numeromancer 942 days ago
It says more than that:

"The returned string pointer might be invalidated or the string content might be overwritten by a subsequent call to getenv()"

You don't even need threads for this to be unsafe; another call to the same function may invalidate earlier-gotten pointers. I don't see how to interpret this as anything but broken.
1 comments
Someone 941 days ago
I think it’s borderline broken. Such APIs are defensible if you don’t have threads and memory is very scarce.

Reading https://man.freebsd.org/cgi/man.cgi?getenv(3) it was introduced in Version 7 AT&T UNIX (https://en.wikipedia.org/wiki/Version_7_Unix). That didn’t have threads.

Now, was memory scarce? The PDP-11 it was designed for could have megabytes of RAM, but I wouldn’t know what the smallest machines this ran on had, and of course, those systems were multi-user.

So, maybe, thisxwas a good choice, but it also could be an early example of using a small system, hacker mindset on machines that didn’t need that anymore.

link
numeromancer 941 days ago
The text implies that any second call to getenv invalidates the returned value of any prior call to getenv; even without threads, without calling setenv, a second call to the function invalidates the return from an earlier call. I re-affirm my conclusion, without qualification: BROKEN.
link