Memory Fundamentals Quiz

Test understanding of heap memory and sbrk

Get every question correct to pass this checkpoint. You can review feedback, revise your answers, and submit again.

1. The break is 1000. A successful request for 64 returns which address and leaves which break? Select one.

Select one answer.

Returns 64; break remains 1000 Returns 1000; break remains 1000 Returns 1000; break becomes 1064 Returns 1064; break becomes 1064

2. After reset, requests for 10 and 6 succeed, zero is rejected, and a request for 20 fails at sbrk. What is heap_total_requested()? Answer in decimal bytes.

3. For that same sequence (successful 10, successful 6, rejected zero, failed positive 20), how many growth attempts are counted?

4. A size_t request exceeds INTPTR_MAX. What should happen before calling sbrk? Select one.

Select one answer.

Reject it without changing either counter Cast first and accept whatever signed value results Count the bytes but make no system call Clamp it to INTPTR_MAX and report full success

5. The successful-byte counter is T. Which check avoids size_t addition overflow before adding n? Select one.

Select one answer.

T == 0 is required for every request n > SIZE_MAX - T T + n > SIZE_MAX after unsigned addition n < INTPTR_MAX is always sufficient

6. After several requests, heap_init is called again. What changes? Select one.

Select one answer.

Both counters reset; the existing break stays where it is The break returns to process startup Every acquired byte is zeroed The attempt counter resets but successful bytes remain

7. A, B, C occupy consecutive blocks and C is live. Why not release interior B by lowering the break through it? Select one.

Select one answer.

B first needs a power-of-two capacity That would remove storage still owned by C B can never become reusable Every free must occur in allocation order

8. Two raw one-byte growth requests both succeed. What does that establish? Select one.

Select one answer.

Both bytes must contain zero Each call acquired one byte; general object alignment is not promised Both results must be 16-byte aligned Both results can independently be passed to libc free

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