How to add path an included library in kernel? - c++

Question

I found many example, how to add this in host on C, but syntax C++ differ than C. I want to add external library in my kernel file.
It's part of my code:
std::ifstream sourceFile(name);
std::string sourceCode(
std::istreambuf_iterator<char>(sourceFile),
(std::istreambuf_iterator<char>()));
Program::Sources source(1, std::make_pair(sourceCode.c_str(), sourceCode.length() + 1));
// Make program of the source code in the context
Program program = Program(context, source);
// Build program for these specific devices
errcode = program.build(devices);
if (errcode != CL_SUCCESS)
{
cout << "There were error during build kernel code. Please, check program code. Errcode = " << errcode << "\n";
cout << "BUILD LOG: " + program.getBuildInfo<CL_PROGRAM_BUILD_LOG>(devices[0]) + "\n";
getchar();
return;
}
// Make kernel
Kernel kernel(program, "vector_add");
How to add path of external library in this code?
In the next step i think, that need to add the second source in Program::Sources. Has anyone written this?

Answer 1

Based on OpenCL 1.2 specification (also the same for 2.0),
-I dir
Add the directory dir to the list of directories to be searched for header files.
You cannot include any ".cl" into another ".cl", but you can #include "Header.h" as much as you want where you can havesome functions or #define, etc.
Note that the code in those header must be in OpenCL C similar to your kernel (except if using OpenCL 2.2, where you can use OpenCL C++).
And lastly, except if you use OpenCL 2.0 and greater, you can't call kernel function inside a kernel, so they must be ordinary function void foo().
So in your case, you could do this:
Program program = Program(context, source);
errcode = program.build(devices, "-I C:\Path\To\My\Include\Header);
And to answer your second question
In the next step i think, that need to add the second source in Program::Sources. Has anyone written this?
You can push_back sources.push_back({ kernelSource.c_str(), kernelSource.length() + 1 }); as much kernel source code as you want into a single sources vector that you provide to the program. But at the end, you can make multiple kernels with this program, since you need to provide a single kernel name per cl::Kernel such as:
Kernel kernel_add(program, "vector_add");
Kernel kernel_sub(program, "vector_sub");
So that mean kernel_add and kernel_sub are build in same time, but they are two different kernels at the end.