IAR Embedded Workbench for RX 5.20IAR C/C++ DevelopmentC/C++ standard library functionsDLIB runtime environment—implementation detailsAtomic operationsAtomic operationsIn this section: Atomic operations using the files stdatomic.h and atomic are not available in the IAR C/C++ Compiler for RX. The predefined preprocessor symbol __STDC_NO_ATOMICS__ is always defined to 1. This is true both in C and C++.