>Many modern systems implement longjump via "forced unwinding"
>("Forced unwinding is a single-phase process (phase 2 of the normal
>exception-handling process").
They may well do so, but that would require C++ exceptions to be supported (or at least the stack unwinding part) wouldn't it?
BOOST_NO_EXCEPTIONS is generally used on systems like WINCE where there is no C++ exception support at all.

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