On Sun, Jul 20, 2025 at 09:27:41AM +0100, Sam James wrote: > This seems to have introduced https://github.com/tytso/e2fsprogs/issues/235. Heh, section 7.23.1 paragraph 4 of the latest C2y draft says that stdin/stdout/stderr “are expressions of type "pointer to FILE" that point to the FILE objects associated, respectively, with the standard error, input, and output streams.” The use of "expression" should have been the warning sign that a symbol that can be mostly used as a pointer is not simply a pointer. Later in footnote 318, they say [stdin/stdout/stderr] “need not be modifiable lvalues to which the value returned by the fopen function could be assigned.” "need not be" is the magic phrasing that means musl and glibc are both following the spec. IOWs, every C programmer should reduce the amount of brainpower they spend on their program's core algorithm so that they can all be really smart about this quirk. So yeah, you're right. But we could also do: fd = open(logfile, O_WRONLY | O_CREAT | O_APPEND, 0666); dup2(fd, STDOUT_FILENO); dup2(fd, STDERR_FILENO); and skip all this standards-worrying. I would have just done that, but for fear that somewhere there might be a library that actually *does* do freopen and this trick won't work. Yaaay, it's 2025 and we all still suuuuuuuck. --D
