101. What is the output of: printf("%d", (int){1.5});
- a) 1
- b) 1.5
- c) Compilation error
- d) Undefined behavior
Answer: A - The compound literal converts 1.5 to int (truncates to 1).
102. Which of these is NOT a valid C11 atomic flag operation?
- a) atomic_flag_test_and_set()
- b) atomic_flag_clear()
- c) atomic_flag_load()
- d) atomic_flag_init()
Answer: C - atomic_flag has no load operation (only test_and_set/clear).
103. What is the purpose of the 'thread_local' keyword?
- a) Thread synchronization
- b) Thread-specific storage
- c) Thread creation
- d) Thread termination
Answer: B - thread_local (C11) declares variables with thread storage duration.
104. What is the output of: printf("%d", 1 << 1 << 1);
- a) 1
- b) 2
- c) 4
- d) 8
Answer: C - Left-associative: (1<<1)=2, then 2<<1=4.
105. Which function is used to query infinity in C99?
- a) isinf()
- b) isInfinite()
- c) fpclassify()
- d) inf()
Answer: A - isinf() macro from math.h tests for infinity.
106. What is the value of: (int[]){1}+1
- a) 1
- b) 2
- c) Pointer to second element
- d) Compilation error
Answer: C - Array decays to pointer, +1 gives pointer to (non-existent) second element.
107. Which of these is NOT a valid C11 thread exit reason?
- a) thrd_success
- b) thrd_error
- c) thrd_failed
- d) thrd_busy
Answer: D - thrd_busy is not a standard exit code (others are).
108. What is the output of: printf("%d", 1 + 2 * 3 % 4);
- a) 1
- b) 2
- c) 3
- d) 4
Answer: C - * and % same precedence: 2*3=6, 6%4=2, then 1+2=3.
109. What is the purpose of the 'mtx_t' type in C11?
- a) Mutex synchronization
- b) Memory allocation
- c) Thread creation
- d) Atomic operations
Answer: A - mtx_t is the mutex type for thread synchronization.
110. What is the output of: printf("%d", 1 << 63); (64-bit long)
- a) -9223372036854775808
- b) 9223372036854775808
- c) Undefined behavior
- d) Implementation defined
Answer: A - Shifting 1 into sign bit gives LONG_MIN (-2^63) in two's complement.
111. Which function is used to copy wide character strings?
- a) wcscpy()
- b) wscpy()
- c) wcpy()
- d) wstrcpy()
Answer: A - wcscpy() copies wide character strings (wchar_t strings).
112. What is the value of: (int){1} = 2
- a) 1
- b) 2
- c) Lvalue required error
- d) Compilation error
Answer: C - Compound literals are not modifiable lvalues.
113. Which of these is NOT a valid C11 condition variable function?
- a) cnd_wait()
- b) cnd_signal()
- c) cnd_notify()
- d) cnd_broadcast()
Answer: C - cnd_notify() doesn't exist (correct is cnd_signal()).
114. What is the output of: printf("%d", 1 ? 2 : 3 ? 4 : 5);
- a) 2
- b) 3
- c) 4
- d) 5
Answer: A - 1 is true → first branch taken (2), second ternary not evaluated.
115. What is the purpose of the 'tss_t' type in C11?
- a) Thread-specific storage
- b) Thread synchronization
- c) Thread creation
- d) Thread termination
Answer: A - tss_t manages thread-specific storage keys.
116. What is the output of: printf("%d", 1 << 1 << 1 << 1);
- a) 2
- b) 4
- c) 8
- d) 16
Answer: C - Left-associative: (((1<<1)<<1)<<1) → 1→2→4→8.
117. Which function is used to concatenate wide character strings?
- a) wcscat()
- b) wscat()
- c) wcat()
- d) wstrcat()
Answer: A - wcscat() concatenates wide character strings.
118. What is the value of: (int[]){1}[0] = 2
- a) 1
- b) 2
- c) Lvalue required error
- d) Compilation error
Answer: B - Array elements from compound literals are modifiable (value becomes 2).
119. Which of these is NOT a valid C11 thread yield function?
- a) thrd_yield()
- b) thrd_sleep()
- c) thrd_sleep_for()
- d) thrd_sleep_until()
Answer: B - thrd_sleep() doesn't exist (correct are yield/sleep_for/sleep_until).
120. What is the output of: printf("%d", 0 ? 1 : 1 ? 2 : 3);
- a) 1
- b) 2
- c) 3
- d) 4
Answer: B - Right-associative: 0?1:(1?2:3) → 1 is true → 2.