Hey there, since you're planning to migrate from QNX 6.6 to 7.0 Neutrino and want to focus on platform-independent kernel and API changes, here's a clear breakdown of the key points you need to prioritize:

Core Kernel & API Updates #

• POSIX Compliance Boost: QNX 7.0 is fully compliant with POSIX.1-2017, while 6.6 was built on older POSIX standards. This brings changes to several standard APIs:
  • pthread attribute functions like pthread_getattr_np() now align with the latest spec, so you might need to adjust how you fetch and modify thread attributes.
  • File system calls like open() support new POSIX-standard flags that weren't available in 6.6, which can improve how you handle file access modes.
• Memory Management Tweaks:
  • mmap() gains the MAP_SHARED_VALIDATE flag, which adds stricter validation for shared memory mappings—this isn't present in 6.6 and can help catch invalid mapping errors earlier.
  • The malloc() family now includes malloc_usable_size(), a POSIX-defined function that lets you get the actual usable size of an allocated block; this wasn't available in 6.6.
• Process & Thread Improvements:
  • Process info APIs like proc_self() return more consistent data across edge cases (e.g., zombie processes) compared to 6.6, where some scenarios would return inconsistent values.
  • QNX 7.0 adds support for the POSIX SCHED_DEADLINE scheduling policy, a feature missing in 6.6. If your code uses custom scheduling logic, you'll want to verify it doesn't rely on outdated policy assumptions.

Deprecated or Removed APIs #

• Legacy QNX-Specific Calls: Several old QNX-only APIs are either deprecated or removed:
  • MsgSendPulse() has been superseded by MsgSendPulse_r(), which offers better error handling. While 6.6 supported both, 7.0 strongly encourages using the _r variant.
  • The non-POSIX ThreadCreate() is deprecated; you should fully switch to pthread_create() for thread creation (though 6.6 had both, 7.0 pushes full POSIX adherence).
• File System API Changes: The legacy openfd() function is deprecated in 7.0—use open() with appropriate flags instead. Also, some devctl() commands for file systems have been replaced with more POSIX-compliant alternatives.

Behavior Shifts (No API Signature Changes, But Logic Differences) #

• Signal Delivery: In 6.6, signals sent to a multi-threaded process could be delivered to any thread by default. QNX 7.0 follows stricter POSIX rules, where signals are delivered to the thread that registered the handler (if specified). This could break code that relies on the old, more arbitrary delivery behavior.
• Error Code Consistency: Many APIs now return standard POSIX error codes instead of QNX-specific ones. For example, pipe() in 6.6 might return a QNX-unique error, but 7.0 uses standard codes like EMFILE or ENFILE as defined by POSIX.

Migration Tips #

• QNX provides a Migration Toolkit in the SDK that automatically scans your code for deprecated or removed APIs—definitely run this first to catch obvious issues.
• Prioritize testing multi-threaded, I/O-heavy, and memory-intensive code, as the changes to signal handling and memory management are the most likely to introduce subtle bugs.

内容的提问来源于stack exchange，提问作者sarjoon