std::align and std::aligned_storage for aligned allocation of memory blocks

Question

I\'m trying to allocate a block of memory of size size which needs to be Alignment aligned where the size may not be defined at compile time. I kno

Answer 1

If it HAS TO BE a C++11 solution, then ignore this answer.

If not... I don't know if you already know this, but here is one option:

void * aligned_malloc( size_t size, size_t alignement )
{
    void * p = malloc( size + --alignement );
    void * p1 = (void*)( ( (size_t)p + alignement ) & ~alignement );

    ((char*)p1)[ -1 ] = (char)((char*)p1 - (char*)p);

    return p1;
}

void aligned_free( void * pMem )
{
    char * pDelete = (char*)pMem - ((char*)pMem)[ -1 ];
    free( pDelete );
}

Perhaps malloc and free are not 100% portable, but it's easy to handle such cases with preprocessor directives.