4. General Concepts

4.3. Extended Security Controls

No extended security controls are implemented.

4.9. Measurement of Execution Time

Process and thread execution time is measured by updating the running time on each clock tick. The running time of the active thread and process on each processor is incremented by the duration of the system clock tick.

The CPU time consumed by interrupt handlers is charged to the thread and process that is currently active on the CPU.

The CPU time consumed by kernel calls is charged to the thread and process performing the kernel call.

The CPU time consumed by system services not implemented by the kernel is charged to the thread in the server process that implements the system service.

4.11. Pathname Resolution

A pathname that begins with two successive slashes is treated as if it begins with a single slash.

4.14. Seconds Since the Epoch

The value of seconds since the Epoch is aligned with the current actual time by a 64-bit offset value that represents the offset, in nanoseconds, from the Epoch to the system boot time.

This offset value is initialised by the platform specific initialisation code within the board support package, for example, by reading RTC hardware if present.

A clock_settime() call using the CLOCK_REALTIME clock will set this offset to specified absolute time minus the current monotonic time since booting.

The offset from the Epoch can also be modified by the QNX specific ClockAdjust() kernel call. This applies a delta to the offset value on each system clock tick, for a specified number of ticks to perform a gradual adjustment of the offset value.

4.17. Tracing

The Trace (TRC) option isn't implemented.

4.18. Treatment of Error Conditions for Mathematical Functions

4.18.1 Domain Error
The return value for a domain error is NaN.
4.18.3 Range Error
  • Result Underflows:
    • The return value for a result that underflows is 0.0.
    • errno is set to ERANGE when (math_errhandling & MATH_ERRNO) is non-zero.
    • The "underflow" floating point exception is raised when (math_errhandling & MATH_ERREXCEPT) is non-zero.