Use ptrdiff_t instead of ssize_t (#6)

frabert · rigtorp · commit 10c00a5c0f1b · 2019-07-30T11:56:19.000+03:00
* Use `ptrdiff_t` instead of `ssize_t`

`ssize_t` is a POSIX extension and is not supported on MSVC, use `ptrdiff_t` instead

* Fix missing include and qualifier
diff --git a/include/rigtorp/SPSCQueue.h b/include/rigtorp/SPSCQueue.h
@@ -24,6 +24,7 @@ SOFTWARE.
 
 #include <atomic>
 #include <cassert>
+#include <cstddef>
 #include <stdexcept>
 #include <type_traits>
 
@@ -43,7 +44,7 @@ template <typename T> class SPSCQueue {
     assert(alignof(SPSCQueue<T>) >= kCacheLineSize);
     assert(reinterpret_cast<char *>(&tail_) -
                reinterpret_cast<char *>(&head_) >=
-           static_cast<ssize_t>(kCacheLineSize));
+           static_cast<std::ptrdiff_t>(kCacheLineSize));
   }
 
   ~SPSCQueue() {
