C10: Core Utilities

C10 (Caffe2 + ATen = C10) is the core library that provides fundamental utilities and data types used throughout PyTorch. It contains device abstractions, memory management utilities, and common data structures.

When to use C10:

• When working with device-agnostic code (CPU, CUDA, XPU, etc.)
• When you need efficient array views without copying data
• When handling optional values or type-erased containers
• When writing code that needs to work across different PyTorch backends

Basic usage:

#include <c10/core/Device.h>
#include <c10/util/ArrayRef.h>

// Device abstraction
c10::Device device(c10::kCUDA, 0);
if (device.is_cuda()) {
    std::cout << "Using CUDA device " << device.index() << std::endl;
}

// Efficient array views (no copy)
std::vector<int64_t> sizes = {3, 4, 5};
c10::ArrayRef<int64_t> sizes_ref(sizes);

// Optional values
c10::optional<int64_t> maybe_dim = 2;
int64_t dim = maybe_dim.value_or(-1);

Header Files

• c10/core/Device.h - Device abstraction
• c10/core/DeviceType.h - Device type enumeration
• c10/util/ArrayRef.h - Non-owning array reference
• c10/util/OptionalArrayRef.h - Optional array reference
• c10/util/Optional.h - Optional value wrapper
• c10/util/Half.h - Half-precision float
• c10/util/Exception.h - Error checking macros (TORCH_CHECK, TORCH_INTERNAL_ASSERT, etc.)
• c10/cuda/CUDAGuard.h - CUDA device guards (see {doc}../cuda/index)
• c10/cuda/CUDAStream.h - CUDA stream management (see {doc}../cuda/index)
• c10/xpu/XPUStream.h - Intel XPU stream management
• ATen/core/ivalue.h - IValue for TorchScript interop

C10 Categories

:maxdepth: 1

device
guards
streams
types
utilities