userinput.c

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>

void catchSIGINT(int signo)
{
	char* message = "SIGINT. Use CTRL-Z to Stop.\n";
	write(STDOUT_FILENO, message, 28);
}

void main()
{
	struct sigaction SIGINT_action = {0};
	SIGINT_action.sa_handler = catchSIGINT;
	sigfillset(&SIGINT_action.sa_mask);
	//SIGINT_action.sa_flags = SA_RESTART;
	sigaction(SIGINT, &SIGINT_action, NULL);

	int numCharsEntered = -5; // How many chars we entered
	int currChar = -5; // Tracks where we are when we print out every char
	size_t bufferSize = 0; // Holds how large the allocated buffer is
	char* lineEntered = NULL; // Points to a buffer allocated by getline() that holds our entered string + \n + \0

	while(1)
	{
		// Get input from the user
		while(1)
		{
			printf("Enter in a line of text (CTRL-C to exit):");
			numCharsEntered = getline(&lineEntered, &bufferSize, stdin); // Get a line from the user
			if (numCharsEntered == -1)
				clearerr(stdin);
			else
				break; // Exit the loop - we've got input
		}

		printf("Allocated %zu bytes for the %d chars you entered.\n", bufferSize, numCharsEntered);
		printf("Here is the raw entered line: \"%s\"\n", lineEntered);
		lineEntered[strcspn(lineEntered, "\n")] = '\0'; // Remove the trailing \n that getline adds
		printf("Here is the cleaned line: \"%s\"\n", lineEntered);

		free(lineEntered); // Free the memory allocated by getline() or else memory leak
		lineEntered = NULL;
	}
}