[boost] Silent change in boost 1.36 alignment_of<> template with gcc 4.3

Subject: [boost] Silent change in boost 1.36 alignment_of<> template with gcc 4.3
From: Jon Biggar (jon_at_[hidden])
Date: 2008-11-08 12:30:46

In boost 1.36, boost::alignment_of<> was changed to use the builtin 
__alignof__() if gcc version was 4.3 or greater rather than using 
calculating alignement using:

template <typename T>
struct alignment_of_hack
{
     char c;
     T t;
     alignment_of_hack();
};

Unfortunately, this broke some code I had written that did structure 
introspection, because gcc's __alignof__() returns 8 for double on the 
x86 architecture, but actually only aligns doubles on 4 byte boundaries 
inside structures.

What do people think about adding a struct_alignment_of<> template that 
uses the old logic to compute alignment inside a struct?

-- 
Jon Biggar
jon_at_[hidden]
jon_at_[hidden]
jonbiggar_at_[hidden]