Operating-system calls

You must substitute DCE thread-jacket routines for all operating-system calls within the thread-safe application. Thread-jacket routines take the name of a system call, but they call the DCE pthread_lock_global_np() function to lock the global mutual exclusion lock (mutex) before they call the actual system service. (Mutexes serialize thread execution by ensuring that only one thread at a time executes a critical section of code.) The DCE include file, pthread.h, defines the jacketed versions of system calls.