Fortran OpenMP Barrier Latency Standardization: Bounded vs Implementation-Defined Behavior Since Fortran 2018
Portability Gap in Barrier Synchronization Guarantees The Fortran 2018 standard refined OpenMP thread synchronization semantics but left barrier latency as implementation-defined. This creates a compatibility boundary where high-performance codes cannot rely on predictable wait times across GNU gfortran, Intel Fortran, and other compilers. gfortran defaults