stdio workaround for tty buffer line limit.

raw_stdin_cat.c

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

/*
claude haiku 4.5 prompt:

make me C program with do:
- save termios settings of current terminal
- reset icanon on terminal settings, and vmin to 1
- read stdin and write to stdout, until get 0x04 character
- restore termios settings and finish executing
*/

int main(void) {
    struct termios original_settings, new_settings;
    int exit_code = 0;
    
    /* Save original terminal settings */
    if (tcgetattr(STDIN_FILENO, &original_settings) == -1) {
        perror("tcgetattr");
        return 1;
    }
    
    /* Copy settings for modification */
    new_settings = original_settings;
    
    /* Disable canonical mode (ICANON) and set VMIN to 1 */
    new_settings.c_lflag &= ~ICANON;  /* Reset ICANON flag */
    new_settings.c_cc[VMIN] = 1;       /* Set minimum characters to read to 1 */
    
    /* Apply new settings */
    if (tcsetattr(STDIN_FILENO, TCSANOW, &new_settings) == -1) {
        perror("tcsetattr");
        exit_code = 1;
        goto restore;
    }
    
    /* Read from stdin and write to stdout until EOF (0x04) */
    unsigned char ch;
    ssize_t bytes_read;
    
    while ((bytes_read = read(STDIN_FILENO, &ch, 1)) > 0) {
        if (ch == 0x04) {  /* EOF character (Ctrl+D) */
            break;
        }
        
        if (write(STDOUT_FILENO, &ch, 1) == -1) {
            perror("write");
            exit_code = 1;
            break;
        }
    }
    
    if (bytes_read == -1) {
        perror("read");
        exit_code = 1;
    }
    
restore:
    /* Restore original terminal settings */
    if (tcsetattr(STDIN_FILENO, TCSANOW, &original_settings) == -1) {
        perror("tcsetattr restore");
        return 1;
    }
    
    return exit_code;
}