A static variable in itkNiftiImageIO.cxx

Engineering
1

static std::string prev;
if (prev != this->GetFileName())
{
#if defined(ITK_USE_VERY_VERBOSE_NIFTI_DEBUGGING)
DumpNiftiHeader(this->GetFileName());
#endif
prev = this->GetFileName();
}

this “prev” useless maybe, damaging Thread Safety

2

Is this related to NRRD thread-safety discussion on GitHub PR?

3
1 Like
4

Yes, itkNiftiImageIO’s `static std::string prev;` is not thread-safe.

Since function-level statics are shared by threads, suppressing DumpNiftiHeader in a multi-threaded ITK pipeline requires the introduction of hidden shared state. Not worth it.

It was the proper decision to remove it. Thread safety > small debug optimization is the reason ITK IO must be re-entrant.