How to get character from keyboard buffer without program pause

[mhnCF]

I need a function that immediately returns either a character existing in the keyboard buffer or a -1
This so I can qualify input before it is echo-ed to the console display.
I found this code but it mysteriously echos characters to the console and I can't figure out why:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>

int main() {
    int input;
    int flags = fcntl(STDIN_FILENO, F_GETFL, 0); // Get the current file status flags

    if (flags == -1) {
        perror("fcntl");
        return 1;
    }

    // Set the non-blocking flag
   flags |= O_NONBLOCK;

    if (fcntl(STDIN_FILENO, F_SETFL, flags) == -1) {
        perror("fcntl");
        return 1;
    }

    while (1) {
        char c;
        int bytesRead = read(STDIN_FILENO, &c, 1); // Try to read one character

        if (bytesRead == 1) {
           printf("Character in buffer: %c\n", c);
        }

        // Your other code here (non-blocking)
         input = getchar();  // Read a single character and do nothing with it, however, It still gets "Printed"
        
    }

    return 0;
}

Thanks for your help

 

[EISENFELD]

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <termios.h>

// Returns: -1 if no character available, otherwise returns the character
int kbhit(void) {
    struct termios oldt, newt;
    int ch;
    int oldf;
    
    // Save old terminal settings
    tcgetattr(STDIN_FILENO, &oldt);
    
    // Set new terminal settings for non-blocking, non-echoing input
    newt = oldt;
    newt.c_lflag &= ~(ICANON | ECHO);
    tcsetattr(STDIN_FILENO, TCSANOW, &newt);
    
    // Set non-blocking mode
    oldf = fcntl(STDIN_FILENO, F_GETFL, 0);
    fcntl(STDIN_FILENO, F_SETFL, oldf | O_NONBLOCK);

    // Try to read a character
    ch = getchar();

    // Restore old terminal settings
    tcsetattr(STDIN_FILENO, TCSANOW, &oldt);
    fcntl(STDIN_FILENO, F_SETFL, oldf);

    // Return the result
    if(ch != EOF) {
        return ch;
    }
    return -1;
}

// Example usage:
int main() {
    printf("Press keys (press 'q' to quit)...\n");
    
    while(1) {
        int c = kbhit();
        if(c != -1) {
            printf("Got character: %c\n", c);
            if(c == 'q') break;
        }
        // Your other code can go here
        usleep(10000);  // Small delay to prevent CPU hogging
    }
    
    return 0;
}