Count is an alias for an atomic integer. All bsls_review macros declare a static local Count variable that is used to track how many times that review has failed. This count gets updated through the bsls::Review::updateCount function.
Count
bsls_review
bsls::Review::updateCount
Declared in <bsls_review.h>
<bsls_review.h>
typedef bsls::AtomicOperations::AtomicTypes::Int Count;