This release includes some refactoring of the exception hierarchy of the main project (STLSoft) and several sub-projects (COMSTL, UNIXSTL and WinSTL).
The root exception used to be stlsoft::os_exception, as a nod to the fact that the two main sub-projects - UNIXSTL and WinSTL - are STL extensions over UNIX and Windows APIs. However, that's never seemed to sit comfortably, so this is now changes. The root exception is stlsoft::project_exception, from which stlsoft::os_exception derives.
The exceptions in UNIXSTL and WinSTL continue to derive from stlsoft::os_exception, but those of COMSTL now derive direct from stlsoft::project_exception.
This refactoring underpins further refactoring around exception/error handling, in the Windows Registry library in particular, which itself will underpin functional enhancements to that library (originally requested (and implemented) by Austin Ziegler). This stuff's likely to appear in 1.9.33
The next release (1.9.32) is likely to contain compatibility fixes for SunStudio (on Intel at first; the Solaris stuff's likely to be another week or so).