chdir is only thread safe to the extent that corruption won't occur. If one thread is using relative paths, and another is doing a chdir-based traversal (as us

chdir is only thread safe to the extent that corruption won't occur. If one thread is using relative paths, and another is doing a chdir-based traversal (as using the nftw function, for instance), that first thread's accesses are messed up. This is why POSIX now has various -at functions; the provide stable relative access.