atomicRestrictions(3) Manual Page

All operations on atomic types must be performed using the built-in atomic functions. C11 and C++11 support operators on atomic types. OpenCL C does not support operators with atomic types. Using atomic types with operators should result in a compilation error.

The atomic_bool, atomic_char, atomic_uchar, atomic_short, atomic_ushort, atomic_intmax_t and atomic_uintmax_t types are not supported by OpenCL C.

OpenCL C 2.0 requires that the built-in atomic functions on atomic types are lock-free. In OpenCL C 3.0 or newer, built-in atomic functions on atomic types may be lock-free.

The _Atomic type specifier and _Atomic type qualifier are not supported by OpenCL C.

The behavior of atomic operations where pointer arguments to the atomic functions refers to an atomic type in the private address space is undefined.

Using memory_order_acquire with any built-in atomic function except atomic_work_item_fence requires support for OpenCL C 2.0, or OpenCL C 3.0 or newer and the __opencl_c_atomic_order_acq_rel feature.

Using memory_order_release with any built-in atomic function except atomic_work_item_fence requires support for OpenCL C 2.0, or OpenCL C 3.0 or newer and the __opencl_c_atomic_order_acq_rel feature.

Using memory_order_acq_rel with any built-in atomic function except atomic_work_item_fence requires support for OpenCL C 2.0, or OpenCL C 3.0 or newer and the __opencl_c_atomic_order_acq_rel feature.

Using memory_order_seq_cst with any built-in atomic function requires support for OpenCL C 2.0, or OpenCL C 3.0 or newer and the __opencl_c_atomic_order_seq_cst feature.

Using memory_scope_sub_group with any built-in atomic function requires support for the cl_khr_subgroups extension macro; or for OpenCL C 3.0 or newer and the __opencl_c_subgroups feature.

Using memory_scope_device requires support for OpenCL C 2.0, or OpenCL C 3.0 or newer and the __opencl_c_atomic_scope_device feature.

Using memory_scope_all_svm_devices requires support for OpenCL C 2.0, or OpenCL C 3.0 or newer and the __opencl_c_atomic_scope_all_devices feature.

Using memory_scope_all_devices requires support for OpenCL C 3.0 or newer and the __opencl_c_atomic_scope_all_devices feature.