Regarding Any Unix implementation of tmpfile is probably reentrant that was just a hunch as I admittedly don t know enough about Unix to say that with confidence And precisely for this reason I did not say that in the main article If you see that conversation I was justifying why I wrote in the article that GNU tmpfile is reentrant which is obviously too system specific It was precisely because I don t know if other implementations are reentrant and the only objective thing I can say is that GNU tmpfile is reentrant