Thanks for your reply. I ran a test using an example thread app. I compiled the cond1.c example from http://www.yolinux.com/TUTORIALS/LinuxTutorialPosixThreads.html using musl-gcc on Ubuntu 13.04, 2.6 kernel obviously. The executable runs on 2.6 as well as 2.4. I actually expected some kind of failure on 2.4. Did I pick a poor example or am I not understanding still? On Thu, Mar 20, 2014 at 7:14 PM, Rich Felker wrote: > On Thu, Mar 20, 2014 at 04:58:49PM -0400, John Mudd wrote: > > Probably a dumb question. Is part of the value of musl that I can build > an > > app using musl on linux 2.6 and then run the binary on linux 2.4? > > The version of Linux you build on has no bearing on the binary that > comes out, so that's not a problem. > > However, Linux 2.4 is not officially supported since it lacks a lot of > functionality needed to provide a modern POSIX conforming environment. > The most notable is that it can't do threads. If you're ok with that, > the other problems might be small enough that you don't mind. I > remember some people in Freenode #musl trying out 2.4 recently and > finding that a few of the busybox applets didn't work right, though, > due to missing statfs64 syscall. > > This page has details on which kernel versions added which syscalls: > > http://man7.org/linux/man-pages/man2/syscalls.2.html > > so it may be helpful in evaluating if there's anything critical you'd > be missing. If a syscall has two versions, one with "64" on the end, > musl needs the one that ends in "64". > > This is definitely a topic we could attempt to document better if more > people are interested in trying to use 2.4. > > Rich >