如何在内核中定义/使用函数

Question

考虑以下示例：

std::string kernelCode =
    "void kernel copy(global int* image, global int* result)"
    "{"
        "result[get_global_id(0)] = foo(get_global_id(0));"
    "}";

sources.push_back({kernelCode.c_str(), kernelCode.length()});

cl::Program program(context, sources);

if (program.build({defaultDevice}) != CL_SUCCESS)
{
    std::cerr << "Error while building kernel: " <<
        program.getBuildInfo<CL_PROGRAM_BUILD_LOG>(defaultDevice) << std::endl;
    exit(1);
}
else
{
    qDebug() << "Kernel compiled succesfully\n";
}

如何使用或定义如下函数：

int foo(int id)
{
   //...
}

在内核中使用？

Answer 1

Source可以包含多个函数，因此只需添加前缀：

std::string kernelCode =
"int foo(int id)"
"{"
"    return id + 1;"
"}"
"void kernel copy(global int* image, global int* result)"
"{"
"    result[get_global_id(0)] = foo(get_global_id(0));"
"}";