CST8234 - C Programming LAB 6 PRACTISE LAB

CST8234 - C Programming
LAB 6
PRACTISE LAB
NOT MARKED
LAB OBJECTIVE
By completing this lab, you will learn to:
• Creating multiple process
• Creating pipe for IPC
• Reading and writing to pipes
LAB INSTRUCTIONS:
STATEMENT OF THE PROBLEM:
In this lab we will look at very basic inter-process communication
technique. We will build a program that simulates a sensor that reads a
temperature in a machine, and sends it to another process for
reporting.
We will have a parent process that is responsible for reading the
temperature from the sensor, which is the child process, and prints it to
the screen. The child on the other hand will keep writing a new
temperature reading every second. The child will not print the data at
all, leaving that responsibility to the parent process.
In order to simulate the solution, we will assume that the temperature
reading will start at 20.1 degrees celsius, then it will keep increasing by
0.1 degrees every second.
REQUIREMENTS:
The Following is a complete list of the program requirements:
1. Declare an array that will hold the pipe descriptors of the appropriate
type. Call that array pipefd.
2. Create a pipe using pipefd, the array declared above, and save the
pipe descriptors in it.
3. Create two process and store the pid returned back
4. In the parent process:
1. Make sure to close the writing end of the pipe and store the
reading end descriptor in a variable that is called fdRead.
2. Loop infinitely and keep reading from the child, storing the
readings in a buffer variable.
3. Print the reading whenever it is available.
5. In the child process:
1. Make sure to close the reading end of the pipe and store the
writing end descriptor in a variable that is called fdWrite.
2. Declare two double variables, one for the initial temperature
value which is set to 20.1. A second constant that represent
the increase value which is set to 0.1.
3. Loop infinitely and keep writing the temperature value to the
pipe using a buffer of the appropriate type.
4. Recalculate the temperature value to be the old value + the
increase constant.
5. Make the process sleep for 1 second before it loops again.
The following is a sample of the output of the file.