cl_float4 on host and float4 on device in openCL

Question

So I want to define a struct thats usable on both the host and on the device in openCL that makes use of the built in openCL float4 datatypes.

On the host side, the framework comes with a cl_float4 type but on the device it's just float4.

So if I create a struct like this...

typedef struct
{
   cl_float4 a, b;
} MyStruct;

...and then try to pass that struct into a kernel (via a buffer) I get an error.

If I declare it as follows...

typedef struct 
{
    float4 a,b;
}

...that would work on the device but doesn't work on the host.

So is there a way to get it so that I can make use of openCLs built in vector types on both sides of my program within the same structs?

jprice jprice · Accepted Answer · 2014-10-16T09:24:50

The C preprocessor can help you here, by treating the code differently depending on whether it is being compiled on the host or the device.

Here's some possible solutions:

typedef struct
{
#ifdef __OPENCL_C_VERSION__
   float4
#else
   cl_float4
#endif
      a, b;
} MyStruct;

or:

#ifdef __OPENCL_C_VERSION__
typedef float4 cl_float4;
#endif

typedef struct
{
   cl_float4 a, b;
} MyStruct;

or:

#ifndef __OPENCL_C_VERSION__
typedef cl_float4 float4;
#endif

typedef struct
{
   float4 a, b;
} MyStruct;

or just use cl_float4, and compile the OpenCL code like this:

clBuildProgram(program, 1, &device, "-Dcl_float4=float4", NULL, NULL);