The POSIX monotonic clock is implemented in uClibc and actually works. However, the _POSIX_MONOTONIC_CLOCK define reads 0, so some libraries which rely on it (e.g. Qt) don't use this feature, which can cause some problems. Setting the define to a value makes Qt use the monotonic clock, which does work, so I really think it should be that way... The define is located in "libc/sysdeps/linux/common/bits/posix_opt.h". I caught this on uClibc 0.9.29, but it seems to be identical in the actual version.
glibc defines _POSIX_MONOTONIC_CLOCK to 0 too: $ echo '#include <unistd.h>' | gcc -E -dD - |& grep _POSIX_MONOTONIC_CLOCK any source tree that treats that as 0 == unimplemented is broken, not the C library. please report this to the QT project.