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What this socket lifecycle interview question tests

This is an easy systems-level question that probes basic understanding of file descriptor management and socket cleanup in C. It appears frequently in interviews for roles involving low-level network code, where candidates must demonstrate familiarity with the operating system's socket API and resource lifecycle.

The question requires you to reason about what happens when a socket file descriptor is closed, including the state of the underlying kernel resources, the file descriptor table, and any subsequent operations on that descriptor. Interviewers use this to confirm you understand the distinction between the application-level socket object and the kernel-managed resource it represents.

• File descriptor lifecycle and cleanup
• Kernel resource deallocation
• Behavior of subsequent system calls on closed descriptors
• Difference between invalid and closed file descriptors