pub fn cpu_time() -> NumberExpand description
CPU time in seconds. Equivalent to Ipopt::CpuTime.
On Unix this returns the process’s accumulated user CPU time via
getrusage(RUSAGE_SELF).ru_utime, exactly matching upstream Ipopt’s
CpuTime() (src/Common/IpUtils.cpp). This is what max_cpu_time
is meant to bound — a busy solve accrues CPU time at roughly the wall
rate, but time spent blocked/sleeping does not count.
std exposes no portable CPU-time API, so non-Unix targets (Windows)
fall back to wallclock. That mirrors upstream too: its Windows path
uses clock(), which on the MSVC runtime measures elapsed real time
rather than CPU time, so the two are already equivalent there.