Non-atomically initializes an atomic object pointed to by
obj to a specified value.
void atomic_init(volatile A *obj, C value)
atomic_init function non-atomically initializes the atomic object pointed to by
obj to the value
In these operation definitions:
Arefers to one of the atomic types.
Crefers to its corresponding non-atomic type.
Mrefers to the type of the other argument for arithmetic operations. For atomic integer types,
The functions not ending in explicit have the same semantics as the corresponding explicit function with
The functions that do not have
memory_scopeargument have the same semantics as the corresponding functions with the
memory_scopeargument set to
|With fine-grained system SVM, sharing happens at the granularity of individual loads and stores anywhere in host memory. Memory consistency is always guaranteed at synchronization points, but to obtain finer control over consistency, the OpenCL atomics functions may be used to ensure that the updates to individual data values made by one unit of execution are visible to other execution units. In particular, when a host thread needs fine control over the consistency of memory that is shared with one or more OpenCL devices, it must use atomic and fence operations that are compatible with the C11 atomic operations.|
We can’t require C11 atomics since host programs can be implemented in other programming languages and versions of C or C++, but we do require that the host programs use atomics and that those atomics be compatible with those in C11.
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.
atomic_uintmax_t types are not supported by OpenCL C.
OpenCL C requires that the built-in atomic functions on atomic types are lock-free.
_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.
local atomic_int local_guide; if (get_local_id(0) == 0) atomic_init(&guide, 42); work_group_barrier(CLK_LOCAL_MEM_FENCE);