signal-handling
The project consists of two processes: the parent process P1 and its child process P2 that will run concurrently.
P1:
-
admits two command line parameters as paths to regular files,
-
reads the contents of the file denoted by inputPath,
-
and every couple of unsigned bytes it reads, is interpreted as a 2D coordinate (x,y),
-
for every 10 coordinates (i.e. every 20 bytes) it reads, it applies the least squares method to the corresponding 2D coordinates and calculates the line equation (ax+b) that fits them. This calculation is considered a critical section, and is not to be interrupted by SIGINT/SIGSTOP.
-
then, P1 writes in a comma separated line the 10 coordinates followed by the line equation as a new line of a temporary file created via mkstemp.
(x_1, y_1),....,(x_10, y_10), ax+b
and proceed to the next 20 bytes and repeat.
P2:
-
is forked early by P1, and reads the contents of the temporary file created by P1, line by line,
-
for every line it reads, it calculates the mean absolute error (MAE), mean squared error (MSE) and root mean squared error (RMSE) between the coordinates and the estimated line. This calculation is considered a critical section, and is not to be interrupted by SIGINT/SIGSTOP
-
It then removes the line it read from the file and writes its own output to the file denoted by outputPath as 10 coordinates, the line equation (ax+b) and the three error estimates in a comma separated form:
(x_1, y_1),....,(x_10, y_10), ax+b, MAE, MSE, RMSE
After processing all the contents of the temporary file and making sure that no more input arrives, P2 terminates and prints on screen for each error metric, its mean and standard deviation.