Very Basic Question

OpenCL
1

Hi all,
I’m very new to OpenCL and I’m trying to figure out how I’d write a (very) simple function. Essentially I need to be able to alter the values of the arguments to a function without returning them. Is there an equivalent to the inout parameter in GLSL?

In C it would be

void ContourTree::switchPoints(Point& a, Point& b)
{
	Point switch_point = a;
	a = b;
	b = switch_point;
}

In GLSL it looks like


void switchPoints(inout vec3 a, inout vec3 b)
{
	vec3 switch_pt = a;
	a = b;
	b = switch_pt;
}

I thought that this would work, but it doesn’t seem to for some reason:


void
test( float* a,
	float* b)
{
	float* temp = a;
	a = b;
	b = temp;
}

wherein I call it like so

test(&a, &b);

I’m sure I’m missing something very basic here.

2

It seems to me that you are swapping pointers instead of the values pointed to. Try


void
test( float* a,
	float* b)
{
	float temp = *a;
	*a = *b;
	*b = temp;
}
3

That’s it. Thank you very much.