Q44.Marks: +2.0UGC NET Paper 2: Computer Science and Application 26th June 2025 Shift 1
Which of the following statement is correct for Pthreads?
1.It refers to POSIX standard (IEEE 1002.1c)
2.This standard defines API for thread creation only
3.This is a specification only for thread behavior and not its implementation✓ Correct
4.Operating systems like Solaris, Linux & Mac OS X, except Tru64 UNIX, implement Pthreads
Solution
Correct Option: 3) This is a specification only for thread behavior and not its implementation
Key Points
Pthreads (POSIX Threads) is a standardized API for creating and managing threads in Unix-like systems. It defines the interface and expected behavior (e.g., how functions like pthread_create or pthread_join should operate) but does not dictate the underlying implementation details, which are left to the operating system or library (e.g., kernel-level vs. user-level threading).
Why Not the Others?
Option 1: Incorrect due to the erroneous standard reference (it's IEEE 1003.1c-1995, not 1002.1c). While Pthreads is part of POSIX, the factual error invalidates this.
Option 2: False. The standard covers a full API, including synchronization (mutexes, condition variables), attributes, and cancellation—not just creation.
Option 4: False. Most listed OSes (Solaris, Linux, Mac OS X) implement Pthreads, and Tru64 UNIX also provides a POSIX Threads Library compliant with IEEE 1003.1-1996.
