Operating System [3i Infotech Placement]: Sample Questions 69 - 70 of 81

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Question 69

Operating System

Question

MCQ▾

Which of the following API is used to hide a window?

Choices

Choice (4)

a.

Show Window

b.

Set Window Placement

c.

Move Window

d.

Enable Window

Answer

a.

Explanation

  • ShowWindow shows a window in a certain manner.
  • Example, the function can minimize, maximize, or restore a given window.
  • The function returns if the window had been hidden before the call, or a non-zero value if it had been visible.

Syntax

BOOL WINAPI ShowWindow (

_In_ HWND hWnd,

_In_ int nCmdShow

) ;

Parameters:

  • hwnd:
    • type: HWND
    • A handle to the window.
  • nCmdShow [int]
    • Type: int
    • Controls how the window is to be shown.
    • This parameter is ignored the first time

Question 70

Operating System
Edit

Describe in Detail

Essay▾

What is IPC? What are the various schemes available?

Explanation

Inter Process Communication
  • The term IPC or interprocess communication describes various ways by which different process running on some operating system communicate between each other.
  • Various schemes available are as follows:
  • Pipes:
    • One-way communication scheme through which different process can communicate.
    • The problem is that the two processes should have a common ancestor.
    • This problem was fixed with the introduction of named-pipes.
  • Message Queues:
    • Message queue can used between related and unrelated processes running on a machine.
  • Shared memory:
    • This is the fasted of all IPC schemes.
    • The memory to share is mapped into the address space of the processes.
    • The speed achieved is attributed to the fact that there is no kernel involvement.
    • This scheme needs synchronization- like mutexes, condition-variables, read-write locks, record-locks, and semaphores.

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