Critical region in concurrent programming What best defines a critical region in process synchronization?

Introduction / Context:
In concurrent programming, multiple threads or processes may need to access shared data. The area of code that reads or writes shared resources is called a critical region (or critical section). Correct synchronization prevents race conditions.

Given Data / Assumptions:

• Shared resources include variables, files, devices, or data structures.
• Mutual exclusion mechanisms are used to protect the critical region.
• Semaphore operations (P and V) are one implementation, but not the definition itself.

Concept / Approach:

A critical region is defined functionally by its access to shared resources, requiring mutual exclusion to avoid interleaving hazards. Various primitives enforce this: locks, semaphores, monitors, or atomic instructions. Therefore, the definition centers on “where shared resources are accessed”.

Step-by-Step Solution:

Verification / Alternative check:

Operating systems and concurrency texts define a critical section as any code that accesses shared variables needing mutual exclusion—a direct match to option c.

Why Other Options Are Wrong:

a and b: Not definitional; a well-implemented critical region may be bug-free. d: P/V describe one guarding technique; other mechanisms exist.

Common Pitfalls:

Assuming that only semaphores define critical sections; forgetting that I/O devices are shared resources too.

Final Answer:

A program segment where shared resources are accessed