Which of the following standard C library functions will always invoke a system call when executed f

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Question

Which of the following standard C library functions will always invoke a system call when executed from a single-threaded process in a UNIX/Linux operating system?(A) exit(B) malloc(C) sleep(D) strlen

Accepted Answer

Correct Answer: (A) exit and (C) sleepConcept -- System Calls vs Library Functions:(A) exit -- TRUE: The exit() library function always terminates the current process. To terminate a process, the OS kernel must reclaim resources, close file descriptors, and update process tables. This requires the _exit() system call (or equivalent) to be invoked. Therefore exit() always invokes a system call.(B) malloc -- FALSE: malloc() allocates heap memory. If the existing heap has sufficient free memory (managed by the C runtime), malloc() can satisfy the request without invoking the kernel -- it simply manipulates free lists in user space. A system call (like brk() or mmap()) is only needed when the heap must be extended. Therefore malloc() does NOT always invoke a system call.(C) sleep -- TRUE: sleep() suspends the calling process for a specified duration. To suspend a process, the OS scheduler must be involved. This always requires a system call (nanosleep() or similar) to put the process into the waiting state.(D) strlen -- FALSE: strlen() computes the length of a null-terminated string entirely in user space by iterating through memory. It never needs to interact with the OS kernel and never invokes a system call.

Which of the following standard C library functions will always invoke a system call when executed from a single-threaded process in a UNIX/Linux operating system?(A) exit(B) malloc(C) sleep(D) strlen

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Which of the following standard C library functions will always invoke a system call when executed from a single-threaded process in a UNIX/Linux operating system?(A) exit(B) malloc(C) sleep(D) strlen

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