一，Mat类的create函数

Mat_的create函数：

template<typename _Tp> inline
void Mat_<_Tp>::create(int _rows, int _cols)
{
    Mat::create(_rows, _cols, traits::Type<_Tp>::value);
}

template<typename _Tp> inline
void Mat_<_Tp>::create(Size _sz)
{
    Mat::create(_sz, traits::Type<_Tp>::value);
}

template<typename _Tp> inline
void Mat_<_Tp>::create(int _dims, const int* _sz)
{
    Mat::create(_dims, _sz, traits::Type<_Tp>::value);
}

Mat的create函数：

void Mat::create(int d, const int* _sizes, int _type)
{
    int i;
    CV_Assert(0 <= d && d <= CV_MAX_DIM && _sizes);
    _type = CV_MAT_TYPE(_type);

    if( data && (d == dims || (d == 1 && dims <= 2)) && _type == type() )
    {
        if( d == 2 && rows == _sizes[0] && cols == _sizes[1] )
            return;
        for( i = 0; i < d; i++ )
            if( size[i] != _sizes[i] )
                break;
        if( i == d && (d > 1 || size[1] == 1))
            return;
    }

    int _sizes_backup[CV_MAX_DIM]; // #5991
    if (_sizes == (this->size.p))
    {
        for(i = 0; i < d; i++ )
            _sizes_backup[i] = _sizes[i];
        _sizes = _sizes_backup;
    }

    release();
    if( d == 0 )
        return;
    flags = (_type & CV_MAT_TYPE_MASK) | MAGIC_VAL;
    setSize(*this, d, _sizes, 0, true);

    if( total() > 0 )
    {
        MatAllocator *a = allocator, *a0 = getDefaultAllocator();
#ifdef HAVE_TGPU
        if( !a || a == tegra::getAllocator() )
            a = tegra::getAllocator(d, _sizes, _type);
#endif
        if(!a)
            a = a0;
        try
        {
            u = a->allocate(dims, size, _type, 0, step.p, ACCESS_RW /* ignored */, USAGE_DEFAULT);
            CV_Assert(u != 0);
        }
        catch (...)
        {
            if (a == a0)
                throw;
            u = a0->allocate(dims, size, _type, 0, step.p, ACCESS_RW /* ignored */, USAGE_DEFAULT);
            CV_Assert(u != 0);
        }
        CV_Assert( step[dims-1] == (size_t)CV_ELEM_SIZE(flags) );
    }

    addref();
    finalizeHdr(*this);
}

void Mat::create(const std::vector<int>& _sizes, int _type)
{
    create((int)_sizes.size(), _sizes.data(), _type);
}

感觉应该还有一个Mat::create(_rows, _cols, traits::Type<_Tp>::value); 但是我没找到对应的源码。