var<workgroup>

var<workgroup> declares a mutable variable in the workgroup address-space.

The memory of a var<workgroup> variable is shared between all the invocations of the workgroup, but cross-invocation accesses must be synchronised with the use of atomics or workgroupBarrier().

var<workgroup> can only be declared at module-scope (global) and is visible to all functions in the module.

A var<workgroup> declaration must have an explicit type, and no initializer expression.

The value of the var<workgroup> variable will be automatically zero initialized before execution of the workgroup.

Uses of a var<workgroup> will always result in a runtime expression.