Portable and interruptible wait for a thread

The problem

I'm trying to use a simple, portable way to perform an interruptible sleep for a thread. Another requirement I have is about the use of SIGSTOP/SIGCONT, if the program is suspended the wait must performs without taking into account the suspension. Example: I'm waiting for 5 seconds, after 1 second the program is suspended, after 1 one minute is restored, the wait should run again waiting 4 seconds.

My analisys

std::condition_variable::wait_for() and std::condition_variable::wait_until() methods use a monothonic time only starting from gcc 10 and glibc 2.6 bugzilla. On previous versions or where there's no platform support, i.e. pthread_cond_clockwait(), the system clock is used. Using the system clock however can have side effects like a timeout too early or too late if the system clock is changed by human or automatically (ex. NTP). In addition the wait_for() and wait_until() can trigger too early if we stop the process via SIGSTOP because the system clock or steady clock are evaluated again and since the whole time is running but our process is frozen, when we start the process again using SIGCONT every wait is triggered.

Possible solutions

It seems there's only one way to sleep in a reliable way even on older platforms, calling select system call. In addition select behavior is ok for my requirements and it can be interrupted using the self pipe trick for example.

The question

Is my analysis correct? Am I missing anything?