cross platform conditional infinite loop

Question

So I wrote the following simple program which asks the user for some input and afterwards just asks if they want to do that again or exit.

#include <conio.h> /* or use ncurses for getch() */
#include <errno.h>
#include <stdio.h>
#include <string.h>

#define TRUE 1
#define FALSE 0

void ReadConsoleInput(void) {
  char buffer[83];
  char *result;

  printf("\nInput line of text, followed by carriage return:\n");

  result = fgets(buffer, sizeof buffer, stdin);
  buffer[strcspn(result, "\r\n")] = '\0';

  if (!result) {
    printf(
        "An error occurred reading from the console:"
        " error code %d\n",
        errno);
  } else {
    printf("\nLine length = %d\nText = %s\n", (int)strlen(result), result);
  }
}

int Repeat() {
  printf("Again? (Y/N): \n");
  int ch;
  ch = getch();
  return (ch == 'Y' || ch == 'y') ? TRUE : FALSE;
}

int main() {
  do { /* infinite loop */
    ReadConsoleInput();
  } while (Repeat());
  return 0;
}

The program runs fine under Windows using mingw64 compile, but the behavior changes upon changing conio.h to ncurses.h and compiling it under linux. The program runs the ReadConsoleInput() function fine but after the user hits 'ENTER' the Repeat() function just displays and the program ends before the user can enter any char.

What is happening different under linux?

(Also as an aside, if the infinite loop is not the right technique for what I am trying to do please advise. I feel like most programs don't rely on an infinite loop test to stay open.)

Eventually I plan on expanding the program to storing the text using a tree data structure and learn from there but I would like to maintain cross platform unity as I go.

Answer 1

Continuing from my comment, just get rid of conio.h altogether. It is 100% non-portable except for windoze/DOS. You can use getchar instead of getch and simply account for any remaining '\n' in the input buffer that remains after the user enters Y/N. For example you could make a portable implementation similar to the following:

#include <stdio.h>
#include <string.h>
#include <errno.h>

#define TRUE 1
#define FALSE 0

void ReadConsoleInput(void) {
    char buffer[83];
    char *result;

    printf("\nInput line of text, followed by carriage return:\n");

    result = fgets(buffer, sizeof buffer, stdin);

    if (!result) {
        printf(
            "An error occurred reading from the console:"
            " error code %d\n",
            errno);
    } else {
        buffer[strcspn(result, "\r\n")] = '\0';
        printf("\nLine length = %d\nText = %s\n", (int)strlen(result), result);
    }
}

int Repeat() {
    printf("Again? (Y/N): \n");
    int c, ch;
    ch = getchar();

    /* empty input buffer */
    for (c = getchar(); c != '\n' && c != EOF; c = getchar()) {}

    return (ch == 'Y' || ch == 'y') ? TRUE : FALSE;
}

int main (void) {
    do { /* infinite loop */
        ReadConsoleInput();
    } while (Repeat());
    return 0;
}

(you would want to check that ch is not EOF and handle accordingly to catch the user cancelling input, before you call getchar to empty the buffer)

Example Use/Output

$ ./bin/noconio

Input line of text, followed by carriage return:
a quick brown fox

Line length = 17
Text = a quick brown fox
Again? (Y/N):
y

Input line of text, followed by carriage return:
jumps over a lazy dog

Line length = 21
Text = jumps over a lazy dog
Again? (Y/N):
n

Look things over and let me know if this is what you intended.